If you go with that pinion, you gotta match it with the 26t ring gear:
http://www3.towerhobbies.com/cgi-bin...?&I=LXSXS5&P=Z
That gives a lower ratio than even buggy diffs (GST is 2.89, buggy is 3.31). The lowest I know of are LSP truggy diffs, 43/10.
http://www3.towerhobbies.com/cgi-bin...?&I=LXJBM4&P=Z
http://www3.towerhobbies.com/cgi-bin...?&I=LXJBM3&P=Z
SH Z-Car, Custom Crawler, 8s Savage,
12s XTM XLB 1/7 buggy,
4wd 4-link rear/IFS Pro4 truck,
Custom Hyper 10 Short Course,
Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz