T3.0 is a threaded version of the G3.0
if you usea G3.0 you need HPI parts A990(clutch bell), B021(bearings), 86706(clutch nut), 86891(fly wheel), and 86000(G3 motor mount)
I find you pretty much need the HPI parts to make it fit. When I tried putting my G3.0 in my MT I bought a different flywheel than the part number listed just to find out it didn't fit, different bell to find the same, think, an ofna clutch nut just to have to cut down, and wasted some cash on motor mounts that didn't line up to the holes when on the G3. The flywheel I originally boughts diameter was too big and it hit the gear box for the center gear.

A T3.0 should fit right in the same spot as the T-15 and use the same parts.