After my recent contemplation about whether I should stick with the car beyond the upcoming 2yr mark and continue bringing it more to my like, or sell up and try something different, the conclusion was to go with the former option at least till it's 3-4 years old before reconsidering again.
One area I always felt it's hard to make a real difference is the inherent behaviour/dynamics of the car during cornering. Which is why when I heard about Haldex controllers being used from some MQB owners (mostly Audi TT-RS) with promising results I decided I had to find out for myself, also as I haven't heard of anyone having explored the impact of such a solution on a Superb yet.
After some search I decided to go with DSA mostly due to the background of the developer (previously related with a certain AWD technology of a certain very relevant German manufacturer...), the controller development and tuning done in collaboration with a known German rally racer and the experiences of owners using it that I could read about.
Installation:
The controller itself is like a small external 2.5" HD, roughly around 15mm x 100mm x 70mm.
It connects to the Haldex below the rear left seat and on it is connected a touch screen from which the parameters and different modes are accessed. Installation is very simple as soon as you can figure out how to take off the rear seat bench. After you've unclipped it from the two main clips (they didn't need replacing afterwards as suggested in the service manual) are off there's two brackets (one at each side) that keep the bench down which need a particular way of pushing to go out. Push towards the back of the car and downwards, that way they'll be able to release and the bench can come off.
There is the option to fix the controller on the carpet via 3M tape (supplied) that bites into the carpet (kind of opposite to Velcro), but as it is so small I figured I could queeze it in below the seat foam for a cleaner installation. It seems like there's enough compliance in there to leave it in even if a passenger sits above. Regarding the control screen, it is not needed to be always connected after you've set it up to your like but untill setting up or for permanent use you can route it somewhere close to the driver's seat.
In the photo below I lift the seat slightly to show the controller below it (not really visible), and the cable going out to the left side of the car, tucked away in that plastic panel which has just enough play to host it nicely until the front dash
It then goes up and via the small cubby, over the steering column and in the little centre bottom cubby:
Not invisible for sure but I can live with it being something temporary as I said, once I have experimented with all options I guess I will settle with a setup and probably just disconnect the screen all-together, or I can try to leave permanenently inside the left cubby which does not allow the cable to be visible at all, just that for now I needed it to be somewhere within direct reach.
Settings:
The controller comes with preset values which you can modify to your preference. For starters, the controller is only activated when switching to ESP SPORT or ESP OFF. I have coded my ESP to immediately switch to ESP Sport with one push of the button, and full ESP OFF when holding the button pressed for 2-3 seconds. Regardless of coding, you don't have to worry about forgetting in an aggressive setup during daily driving as the ESP defaults to ON (and thus the controller being OFF) every time the car starts up.
The main parameters are the Minimum and Maximum locking values of the clutch (set between 0-100%) that override the stock values. The minimum locking value set is disregarded (locking is reduced 0-10%) when coming to a stop and when creeping forward.
Another feature is the steering angle reduce factor (menus are all in German for now). By activating this, instead of having a fixed minimum locking of say 60% at all times, the locking percentage is allowed to drop below the minimum locking value as soon as the steering wheel stops being straight, and the ratio at which this happens can be set from 1 (very slow and little reduction) to 20 (immediate reduction of a larger extent).
There's also an option to run the car in FWD mode. I tried that just to remind myself of the misery of my 370bhp GTI in the wet or in general on any road/condition below 60km/h, foot down and... yes, wheelspin bonanza... I also remembered why I had said I won't ever own another FWD car above 250bhp, let alone closer to 400...
You can also choose to keep the rear axle engaged during braking (as stock, Haldex disengages the rear axle when brakes are applied), this would work well on track I imagine.
Finally there's real-time monitoring of the percentage of locking, to understand exactly what's going on and how the parameters affect operation, as well as of engine rpm, torque, oil and coolant temps.
*** A note about locking values: The min/max locking values can be set up to 100%. Setting both at 100% means obviously the clutch is fully engaged at all times. This should NOT be confused with the actual torque split taking place though. Due to the design of the Haldex, there is no way to ever have more than 50% torque at the rear axle because if rear is fully engaged (100%), then both axles share torque equally (50-50). I am thus concluding that any locking value seen at any point, should translate, at best, to half of it in terms of Torque % arriving to the rear axle (minus drivetrain losses where they occur). Still, a greater rear drive bias than the stock management for sure than only momentarily increases clutch locking to anything over 20-30% as I could see from my testing with the controller in stock mode.
Driving:
As expected, there is no difference under normal driving. This is not a suspension modification that you'll feel as soon as you drove a few meters. However, start using the throttle around a corner and you realize immediately there is unusual agility and willingness from the car to rotate, much more than you ever thought the car had to offer. Before, using more throttle than seemed appropriate for sticking to your track, resulted in fighting with the steering wheel to turn the front end of the car towards the inside of the corner. This is now gone.
Up to a point it almost feels as if you've activated some "turning assist" that rotates the rear and keeps you on track but allowing you to accelerate even more at the same time. You simply corner faster. Over-do it, and the tail now easily steps out. Very manageable with a bit of opposite lock and throttle modulation but it will shock you the first few times simply because the car could never do something like that before. It put some big smiles up on my face for sure.
I also believe a thicker rear arb as the one I run accentuates the effect, so be prepared, especially when you've set up a large minimum locking value and no/very little steering angle reduction...
Impressions:
This is an improvement making itself noticeable and appreciated during fast driving (and I don't mean in a straight line). A track is where it would really shine or the right type of b-roads. Used wisely it makes the car faster and more involving, more playful. Used not so wisely it makes it just fun or silly, or potentially dangerous if you don't know what you're doing.
So far for me, the Haldex cars I'd driven (all 5th gen) were great point to point cars. Traction under all conditions but not able to carry much speed around the corner neither being particularly involving. The approach to drive them fast was moderate corner entry, steady throttle till the apex or even till a little after it, and then flooring it just as you touch the corner exit. Very one-dimensional and "automated" so to speak. With the controller, they are still no RWD beasts but they can become something better, more satisfying. The way the car responds now you can start applying throttle much earlier without the car washing wide but actually rotating where you're pointing and going even faster without scrubbing speed off. Or you can over-do it ever so slightly (when conditions allow) in order to have some fun around corners. It allows you to take an approach that was previously not accesible with any other modification and even if can only get use of it rarely, it feels very good to have it at my disposal.
PS. I do need to do a proactive Haldex oil change now just to be on the safe side.
PS.2 My rear tires are not going to be very happy with this mod...