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.. 
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.
Explain to me how a car that is similar weight to a 320bhp VW Golf but has nearly 30bhp less will walk all over it?

Yeah I agree the Golf isn't going to be as good round the track, but then for nearly double the money I should think it would be better...

(You can't compare new for used IMO)
My Ed30 mods have cost me £700 so far as I got a great deal on a 2nd hand Milltek and discount on my remap. I will make around £300 back for my Milltek when the car goes back and over the 3 years I will have the car, it will have cost me £400 to have an extra 80-90bhp to play with over the next 80,000 fun miles.. A bloody bargain in my eyes!!!