driveshaft selection

[Flash68]

I searched and was surprised there was not more talk of this anywhere that I could see. Maybe it's a no brainer and I shouldn't be asking!

Anyway, it seems like I see a lot of guys with less power than me using a 3.5" aluminum driveshaft from Inland or Denny's. Is there a certain level you really should go from steel to aluminum? I have the steel driveshaft that came with my TKO 600 from Keisler. Is there any reason why it's not a good idea to use it? I believe it's a 3". Will fitment issues come into play with 3" exhaust?

Quick specs of my car:

procharged 406 approx 650-700 rwhp
TKO 600
9" rear 3.70 gears
3" exhaust with x-pipe will be run


thanks