Not really, Jonny's S3 would eat a RS4 and spit it out in bits.. Plus spending extra £'s by progressively modding a car isn't really the same as going out and buying a more expensive one in the first place.. Modding is like being a drug addict for a start, you don't really care about how much money you've spent until it's to late.. 
I know have been there and done it
then added up the costs of the cash it costs and resale of the car and no warranty and these days your much better off just buying a faster car
let alone trying to tell your insurance company what the car is worth if its written off.
yes put a chip in and exhaust but any more is total lost money better spent on a TTRS or Porsche.
you can get a Cayman S for 30k which will walk all over a 320Bhp VW or Audi turbo car and you can sell it after for 60% of the cost
Modded cars hard very hard to sell on and sometime sell for less than the base spec model due to low demand.
So not only do you lose 100% of the money you have spent on it you also cannot shift it.