The only way of getting more power out of the V6 engine is to stick new more expensive bits on it. Hence pushing up the price of the R32. As for the R36...we it was only ever rumours!
I think before you start comparing power between the entire VW and Audi group you need to look at the components that make up the car... its purpose in the line up..... and ultimately the most important factor... cost! Yes the R32 probably was limited to being less powerful than the S3. Simply because its meant to be the inferior car, and Audi use the more expensive parts cough cough.
In my opinion, the Ed30 only came about for 2 reasons.
1. It was obviously the 30th anninversary of the golf.
2. The standard Gti was really being put under pressure from the other more powerful (but not better of course) hatchbacks.
VW looked in the old parts bin and put together the ED30 (in short). If they really wanted they could of had a much more powerful golf. i dont think they held back because of the R32 but simply because of the limits of other parts of the golf. IMO the R32 is made not to be the most powerful golf but to offer the driver that little bit more in terms of refinement, and drive i.e. big engine relatively small car. With the addition of the 4WD and the few extras chucked in to the mix the R32 is a very capable car, with one of theeeee sexiest sounding engines your probably likely to hear. The price to pay for all this is the fact that modding them is very very expensive.
In short, I guess what I am trying to say, as many others who have owned both say is the R32 is the best!!! no, only joking there. They are two entirely different cars and setups that share the same body, and offer a different type of enjoyment. Hence why so many times people will just shout go and drive both!!! the comparison is obviously going to be made! in terms of value then the ED30 wins hands down simply for its performance and tunability. If you test drive the R32 and can justify it to yourself to spend that little extra because its not just the speed your after but the composed ride and rock steady handling. Then you are always going to go for the R32.