Shrewiside, I'm a step behind Borat52, I've got a full 2.5" decat, K&N panel filter, running a TD04 with a ESL chip it shifts compared to the standard version.
Within the next 2 weeks I'll have fitted a TD05 running with the appropriate ESL chips, can't wait.
Don't forget about the brakes and suspension to cope with the extra power and enable you to go quicker around the twisties.
Althrough saying that I haven't bothered.....yet