Damn, Ned. You really have changed and going all out now!!

You could get 800rwhp out of a pair of GT35Rs, with damn fine spool. 1000rwhp would be on the upper end at 6.1L, you're on the high side of the map- but if it doesn't live there all the time, I think it's a combo you'd really like. To aid in spool, try to keep the turbos as close to the head as possible.

I do belive Nitrorocket has (#s wise) a similar combo; I'd chat with him about driveability.