Engine mods so far

I bought my 1.9 tdi 110 2003 Octavia 2 weeks ago ,it has less than 70k miles so I thought I would tell you what I have done to the engine .Changed the oil (fully synth ) and all filters, EGR delete kit which took 3 hours of which 2 hours was cleaning out the inlet manifold as it was about 35% blocked with black goo,A Tunit plug and play superchip which is programmable (been using this company since 2001 and no snags ) ,removed the exhaust from the turbo to the first pipe connection and gutted the cat which took about 30 mins. Results EGR delete gave the engine a more guttural voice but ran sweeter .Chipping it gave a severe step in poke. Cat gutting smoothed out the sudden shove in the back acceleration . Overall result.,.,., The turbo starts at about 1400rpm and the push is more linear with a distinct peak of 3000 to 4500rpm and no flatspots. Absolutely NO smoke (smoke is only incomplete fuel usage ,,wastage anyway ) MPG has increased by 6 mpg when not showing off and its a LOT smoother. I think chipping and cat gutting were significant together as to create a greater DP (differential pressure )across the turbo to help spool up and reduce EGT`s by getting the hot gasses out quicker. The gutted cat leaving the cat shell in place will only help exhaust exit speed up time because if the increased surface area available to cool the exhaust gasses which reduces their volume for a given gas flow mass.Going to extremes and fitting a very large bore exhaust can be counterproductive ( those who mention the requirement for backpressure in an exhaust system are living in the history of racing 2 stroke bikes ) dragsters have open exhausts and produce up to 8000bhp. A large bore pipe can set up a sub harmonic frequency that prevents gas flow ( like a straw with a kink in it ) so work out to the peak RPM, times boost pressure in bar which will give liters per 2 revs times 60 to give gas flow per minute.Who have I lost ? .,., Match the max exhaust flow allowed by a certain diameter pipe but don't go bigger.

Now im going to upgrade the brakes