Very few R32 GTS-t's were sold, most were 'Type M'. I've only seen one actual 'GTS-t' in Australia and 2 or 3 in Japan, ALL the rest (over 100) were Type M's. Such was the case that all turbo R33's are Type Ms...
Anyway, the Type M gets Viscous LSD and 4-pot/2-pot calipers on bigger disks, and some interior things like climate control as was already mentioned.
The 'aero bumper, side skirts and rear pods' were available across the range, and alot of Type M's had no body lit at all. So the body kit isn't a good way to see if you have a Type M.
The bottom line is: You'd be crazy to get a regular GTS-t over a Type M unless the GTS-t had 000,000km's on it. The Type M's were most popular because of the brake package and LSD, which put it closer to the (then) R32 GT-R in some areas. The regular GTS-t is basically a GTS with a turbo bolted onto it... nothing more.