Speed at the flick of a switch!!
The only way i can think of to get speed just like that would be nitrous. Providing u do all the normal things, filter, exhaust, chip if there is one, then nitrous is the way to go. It costs between £800 an £1500 but is cheeper than an engine conversion. Basicly when you floor the accelerater the nitrous kicks in and can deliver 25bhp 50bhp 75bhp or 100bhp. ( i'd stick with 25 or 50) The hit is instant and your feel as though your in a different car.
Other kits (the more expensive ones) offer set ups i.e at 25% throtle u can have 25bhp at 50% throtle u can have 50bhp and at full throtle 75bhp. Or u can have say 25bhp at 70% throtle and then 50bhp at full throtle. There are several places in the UK or can do this (just look in the back of some modified car mags) i'm assuming u live in the UK.
For example if your car peaks at 100bhp at 5600rpm then with nitrous your car could peak at 150bhp at 5600rpm, which is up to HGT power!!
Just a thought eh.
