I know what your saying on the 4x4 conversion aswell mate but I have worked with a very similar situation. The reason I say the Evo 1, 2 or is because they are a nice, comfortable power to cospe with. The Evo 1 is 250bhp, Evo 2 is 260bhp and the 3 is 270bhp and the Tommi Makinen edition is only 290bhp
. Before I got rid of my Vectra I had that running 265bhp with no problems what so ever and I left as 2 wheel drive. Also, either car that the Red Top Turbo came from (Calibra or Cavalier/Vectra A) were both 4x4. So you see, you can go so far for very little £££'s and still be able to have your car cope with the extra power.
To give you an idea of how cheap you could make this project, I have done a little bit of research for you
Click here to see how cheap the engines are!!
I also found that a set of uprated brakes will cost you £180 incuding drilled and grooved disks and uprated pads.
Set of 40-60mm lowering springs from Eibach will cost you £180 for the set (standard shocks have been comfirmed they will handle a lowering of no more than 60mm which if fine aslong as you replace with a new set when changing the springs)
Then it's up to you how much you wanna spend of exhaust, filter, dump valve, intercooler, and wheels etc. But if you spend correctly, you could do the whole thing for about £1600-1700