OK - DMS Automotive in Southampton provided me this printout of the tuning opportunity (remap) for a 335i N55 engine..
Looks promising - 375bhp and >400lbb/ft of torque. Probably enough for me!
Incidentally they also offer a remap of the 4.8 S4 engine that adds around 35bhp. Interesting.
Remaps for <1000 quid including VAT. DMS has a good reputation in this area, I know a fair number of porsche folk who swear by their upgrades to the 996TT.
