| Do you want smoothness or just power? Also, where are you based?
Smoothness: Custom remap = Better, response, improved power delivery & a few more ponies/torques (not 20-25 though), same/better economy if you desire. Circa £350.
Power: 15% Pulley & NGK Iridium plugs = 20-25 bhp, better torque from 2000rpm, worse economy. Circa £320.
Do both and you have a winner. Theres only one place I know of that does a decent custom remap (avoid generic maps as they are too hit and miss) but the pulley and plugs can be done anywhere mini related. If you let us know where your based we'll point you to the best, nearest place.
When talking fails, it's time for violence. ~ batou.  | 
