If he's willing to save more and get the spec B I think its worth it, although I'm partial.
For one, the 6-speed is stronger than the 5-speed. Its exactly the same that's in the STi, aside from some different ratios. The Spec B, as long as its and 07+ has a better rear dif than the regular
GT. It has the R180 Torsen diff that the STi has. Thats about the only things that are the same as the STi.
Now the differences between the
GT and the Spec B are as follows:
Spec B has aluminum suspension bits,
GT does not.
Spec B has Bilstein Suspension, while better than the stock
GT suspension,
if he wants better handling, coilovers or struts & springs are the way to go
with either, but out of the box, the Spec B will handle better.
You can get Navigation and manual with the Spec B, Nav only comes with auto on
GT.
Spec B comes stock with sticky summer tires and 18" wheels,
GT comes with sh**y RE92's on 17"
However, they are both 7" wide, so an wider aftermarket rim and tire would be ideal.
07+ Spec b's comes with Alcantara inserts, which
HOLD you in the seat a little better,
GT has only perforated leather.
07+ Spec B's come with defeatable VDC, I'm pretty sure auto GT's are the only models available with that.
Now some might thing some of these things are subjective, but it all comes down to what the person wants. If he's planning on doing heavy modifications both suspension wise and engine wise, I'd go with the cheaper one, but you'll most likely need to upgrade the tranny. However, if he's looking only to get mid 300's, while the 5MT should handle the
POWER fine, the 6MT will
HOLD up a little better.