A remap isn't really on unless your name is Woj.
You need some way of reducing the compression ratio and some way of adjusting the fuelling.
For the first, the options are:
Machine down the existing pistons. This has the undesirable effect of making the top piston land fragile.
Use a spacer to increase the size of the combustion chamber. This has the undesireable effect of reducing squish (you'll loose some power and economy).
Use 16v pistons and rods. This has the undesireable effect of lowering CR too much, and, then, they're still only cast pistons.
Use forged pistons. The only bad thing here is that they're not cheap.
For the second, classically folk have used a Fuel Cut Defender and an Aquamist MF2 to drive a second injector. This is an outdated, outmoded, approach and is expensive for what you get. Alternatives are a piggy back ECU like the ECU Master DET 3 or a standalone like Megasquirt, Microsquirt -- indeed, any standalone will do fine, although you'd really be better off with an MPI head.
You'll also need time on a rolling road to set it up and an upgraded fuel pump.
Turboing an n/a engine is expensive and heartbreaking: the T Jet out of a 500 Abarth (get the engine and gearbox) will fit with some fabrication, and will possibly be cheaper and more reliable.
The search function on the forum will yield a lot more information, but it isn't for the faint of heart or the short of pocket.
