That's big power Roy, even when I pushed my RB20 as hard as I could I didn't get that much Do you still have the standard RB20 box? God knows how that is holding up, I had a wack less power and managed to break a RB25 box
In saying that I don't actually think you will have issues with reliability, pistons, rod and crank should be fine, E85 is the juice of Gods... The bearings may take a beating but who knows, time will tell.