For the power your looking for 600? you wouldn't need the cams and adjustable cam pulleys ,I am on stock cams and made 622hp I remember JP made 630 on stock cams too, for a fraction of the cost of cams I would do a inlet manifold mine is a eBay copy get the ports matched and welded onto the runners with a q45 when I got mine mapped Ryan runs no boost to begin with he said the inlet is working between 20-30hp .I wish I'd left mine BPU as others have said its a blast being single but the supra just seems its best at tt bpu with the £££ put in I wish I'd bought a set of new twins or had them refreshed,and syvecs and make the best out off bpu still a very fast car and it would go to the end of the earth and back without any worries.