Are there any cosmetic differences?

 

Leather steering wheel for the sport, not the base.

Tyler

 

different shift knob. no cruise control on steering wheel. missing 2 speakers.
other than that, it's cosmetically the same inside.

 

yep, the steering wheel, and also (at least the 07's) had a slightly nicer shift knob, and if I remember right, slightly fabric. I think the fabric is the same on all the 08's though...

That's all, as far as I know for purely cosmetic items.
I assume you know about the stereo, mp3 jack, etc......

 

Of course, the Sport Auto has the "F1 inspired" paddle shifters!

 

Regarding installing some type of leather aftermarket cover?

 

Mugen makes leather seat covers. I think they run about $800 though.

 

do a search and there are couple folks that did leather redo rather than just covers.... very nice options out there if you really want them and willing to spend...

like this one....

 

the seat fabric is different on the sport, colour anyway

 

yup...lot of money. I've heard they also don't fit perfectly on the USDM fit...