Not too much more you can do mate, some engines are better than others, mine was a 2004 on 90k when remaped, had a milltek, berks, plenum spacer and pop charger and was 286bhp before and a gnats chuff under 300 after
It's not about numbers its about the drive, have you upgraded the brakes or anything else that will have more of an impact.
I think decats might give you kess toque i'm no expert