In my opinion the non-Vspecs look a bit silly and I would not buy one.
The lack of the lower lip on the front bar is quite striking and takes a lot of the personality away from the front end.
The rear diffuser is a nice bonus and fills the rear end out as well.
The diff, well, it's better than the standard diff I gather and I have never heard of one going bad on a 34. I really cant say that i've tried them back to back.
I mean for the price difference (small) you are going to have to wonder why you'd bother with a non-Vspec. I know now that even if I was going to save 5 or 6k I probably still would've gone with the V-Spec like I did.