Jeez, bringing it forward would be a nightmare I reckon.
Tail shaft isn't a real biggee I s'pose.
I (well, Brunny's) had to do that front and rear when the 4L85e Tranny went in to replace the 5 speed Nissan box on mine.
Bugger dicking around with all the suspension geometry, that would be a prick of thing to get right assuming you still had enough wheel well clearance