Have you actually test drove or even been a passenger in either model?
The S3 is superior to the R32 in everything, which is why there is no real competition between the two instead it is more of A3 3.2 V6 vs R32. The R32 is much less involving and slower, no way in the same league.
i stand corrected, it's the 3.2 A3 which was compared to the R32, but EVO mag tested both and said that the A3 was much less involving than the R32
I don't know who told you £300 would get S3 performance out of a 2.0TFSI, that is completly false. They may use the same size engine but the S3 is much more powerful, especially since S3 owners have been reporting 20-30+ more bhp than what audi claim.
A lot of the tuning companies offer upwards of 250bhp from a remap, i got recommended to 'celtic tuning' for my own 2.0 TFSi from a friend who has dealt with them before, i intend on going to them myself.
As for the 265bhp, no worthy remap company offers that gain so I wouldn't go trusting that figure.
A +1 from me for the S3 as it is now in S-tronic, if you went for the pre facelift they are doing some great bargains (manual only though).
*edit* The 135i has some amazing tuning ability, I've seen it embarass a lambo! and you think remapping an A3 to 265 is impossible?