I hope you've got good fab skills, you're already going to have a nose heavy car and the 510 engine bay is small as it is, You're going to have to section the firewall just to get that big beast to fit. You're probably going to have to do a pretty substantial amount of work to the trans tunnel to get that big ol' RB25 trans to fit, and I'd definitely look hard at a R200 up rear, you can kiss that R160 good bye with anything but a stock RB.
Very much not the option I'd go for anything but goin' fast in a striaght line, but it'll be cool no mater what, so go for it. Pics are a must.
There are a bunch of guys in the portland area, so you're in luck as far as knowledge goes.