if you are going turbo or super charger then the limits become materials and components. as in what will be the first thing to break. when getting up in the hp (300)then you will be looking at billet crankshaft,carrillo rods, forged pistons etc. the clutch will need to be especially strong. then the gearbox must be replaced with something much stronger. driveshaft & u-joints will twist like spagetti, diff won't take it or drive axles etc,etc. probably the block will break. frame will twist, brake will need replacing with racing stuff.
You get the picture. if you really want to go there properly ande reliably with a turbo, the figure closer to 50K plus.
(a nice 93 toyota supra twin turbo drive train,brakes etc might be adapted for a lot less money, 320hp)
rob