Carpenter has one big advantage over Nev, *if* you're in the US, and *if* you have the money: he offers ride-in-ride out service on a product he sells.
If you live in his part of Australia, or, you have a tool set and mindset to DIY, Nev offers much better cost effectiveness in dollar/hp made, especially when combined with good exhaust and intake (as pointed out by
@Steel ). And while Nev would like to sell you his cams and tensioner, he will quietly suggest one can go a long way for performance on a 2.3L motor with just the exhaust and intake and legitimate ECU remap.