on mine, i delipped the pistons, put a cam in, did spring/prods/lifters, and went from stock turbo's to 71/59.
it spooled retarded faster. i currently have rcd 75/59, and it lights them just as effortlessly.
iirc, i'm as close to cam only change as your going to get, and like it has been stated earlier thats about as close to good info as your going to get. which, really, isn't good info.
i didn't feel more up top, but it comes on a hellava lot sooner. though we didn't spec my cam for top end, i had it spec'd to drive the turbo's harder faster. a solid tow cam.