Bought a Superb 2016 L&K last week.

[j.hanratty]

Replaced Mit Silikat Radiator expansion tank with a Mahle pattern part which didn't fit exactly as left side clip that holds it on to frame was slightly short,  so I put a self tapping screw through the top of the clip and some rubber underneath to stop it moving up and down and it now fits perfectly! I reset DSG box and it's slightly better but I will probably get a TVS gearbox remap as it's not an easy thing to get used to. I was driving a 27 year old Lexus Ls400 before and the auto box on that was better. Comfort is pretty good but it does have 19 inch wheels which are just a bit too much and I may replace them with 18 inch wheels. I was even thinking about 17 inch wheels but I think everything on the car is set up for the 18/19 inch wheels.

[numskull]

Why didn't you return the expansion tank for a correct unit instead of bodging it?
What L&K Superb do you have, a Petrol or Diesel? 
What do you think is “wrong” with the gearbox? What are the symptoms? A DSG box is nothing like a traditional slush box. 
What is wrong with the wheels; ride or noise? Reducing the wheel size from 19 to 18 will not improve the ride experience by any noticeable degree. Changing the tyres for something like all seasons would massively reduce tyre roar. 

[j.hanratty]

The tank will work perfectly and I wasn't prepared for another wait for a new one that may well have been just the same. I know it's a semi automatic gearbox but it seems to be set up for getting good mpg above all else, all the usual complaints really. The ride on the 19 inch wheels is harsh at times especially on drain covers potholes etc. Tyre roar isn't a problem. It's a diesel 2.0 150 bhp.

[numskull]

What year, mileage, service history etc. OK, well, we’re here to help and advise on correct parts etc. so just ask. 

Re the DSG, you’ve been used to driving a petrol 290bhp vehicle to a diesel 147bhp vehicle. Has the DSG been serviced? Have you tried Sport mode? 

[j.hanratty]

Dsg has just been serviced car has 28,000 miles on it with a comprehensive service history. I don't think there's anything really wrong with the gearbox it's a matter of me probably adapting to it's characteristics. I haven't tried sport mode but I will. Thanks.

 

[numskull]

Also, is the car in eco mode? If it is, try normal mode before Sport.  Additionally, in my experience, Skoda dealers don’t apply any updates unless there’s a specific issue noted by the owner, then they might check. 
What year is the car? Does it have a 6 speed DSG? 

Edited 8 April by numskull

[Stonechip]

3 hours ago, numskull said:

Why didn't you return the expansion tank for a correct unit instead of bodging it?
What L&K Superb do you have, a Petrol or Diesel? 
What do you think is “wrong” with the gearbox? What are the symptoms? A DSG box is nothing like a traditional slush box. 
What is wrong with the wheels; ride or noise? Reducing the wheel size from 19 to 18 will not improve the ride experience by any noticeable degree. Changing the tyres for something like all seasons would massively reduce tyre roar. 

 Second what @numskull is saying - I have 19 inch wheels and when I changed the original Bridgestone Potenza to Michelin cross climate 2s  the difference was startling - far far quieter and smoother than I expected. TBH  I never would have believed that the choice of tyre could make such a huge difference . Motto for me is Keep the 19 inch wheels for the look and change to Michelin cross climate 2s for the ride.