Fork, if you do even contemplate boosting an SP20, there is a heap to consider. Guyz over @ MX6.com, particularly Jesse (Jesiotrot) has, or had a 626 wagon & I can't remember the donk he had but it handled the turbo with higher comp. It was one particular engine. Pretty sure it was a 2.0L, not sure on model though?
When you boost with anything over 9:1 comp, you have to consider firstly the EMS you will use. You can't simply use your stock management system. Then there is the legalities/engineer cert to consider.
Safest advice @ this stage, aside from working out the expense would be to consider a half-cut so you have the complete turbo system so to speak. The loom/engine/turbo etc. Then you have to wire it in so your instrumentationj works etc.
This is why I suggested looking @ previous threads &/or straight out asking the guyz on performance forums. State what $ you have & where your @ with car & what you want from it.
Lastly, you need to factor in add ons such as heavier clutch, brakes maybe? Suspension? At least look into it. All the best
