I have a fully built 091 right now in a 2 seat rear engine with a 300 hp 2.5 subi. I am so concerned with exploding the R&P with how many ruts there are now. Really what is the weak link in each tranny? I never use reverse so that's not a concern. I am liking the E box for the larger R&P.

Run it till it breaks then buy one. That subi isn't much of a torque monster so it should last awhile.
I don't think the 4e is all that much stronger than a fully built 091.

If you got the funds, I think stepping up to the E is worth it. I've been very happy with my E over the last 4 years, putting apprx. 325hp through it. I've done the main bearings twice, but the first time was right after I bought it in 2005 and can be blamed on the last owner dumping the clutch to get the car into a wheelie. Treated right, I'm not saying dont drive hard, the tranny will last for a long time in your set up. And for the record, I've never had a problem with the reverse...again, just have to use common sense and it will treat you right.

I think I treat all my equipment right but I just want a little more assurance when dunning hard.

I ran a full built 091 in my 2 seat 335hp suby for 2 years until the stock r/p let go, but I did drive it VERY hard always beating it through the whoops and some clutch abuse. I would just run it till it breaks, may never if you drive smart. I thinks the E box is alot stronger than a 091 so if the money is burnin a hole go for it.

I drive the crap out of mine. Just thinking. I always want something more.

If you have the $, then over build it. I have a 250 hp honda 3.5 on a 1,500lb car with the 2D. It is just nice to know that I do not have a weak link that is going to break at some point. My last car was a 250hp VW with a swing axle that blew up every chance it got. I just wasn't going to deal with that B.S. again. I like to drive, not fix sh*t.

My turn-
The 091 is a good box
weak points
mainshaft bearing
reverse
ring & pinion
gear tooth profile
Main case
inputshaft
these can be increased in strength by current aftermarket products
MD4E
weak point in comparison
reverse

What little I know about your car it is a good canidate for a "E"
If you decide to turbo, then most the guys run -2D