Bennet,
I disagree, sorry buddy..
I think he wants to blow his mates cars on dual carriageways rather than take it round the ring so that leaves either N20 or a supercharger.
I cant be bothered to read both pages but if he had a budget of £3k, he would never have been able to afford even a used vortech. You may be able to buy the supercharger itself for that much but what about everything else that goes with it? I mean, Nurrish's remap was nearly £700.
That only leaves N2O and even better if he strips it of weight
I do agree though that if he wants a faster track time he should go with suspension and tyres etc, just my 2p, I know I'll probably get ripped to pieces