I have the 7945TH and its worth the money for sure, I just bought a 7955 and a 7940 used for an older 1/8 nitro buggy and stepped up to a 7.4V hump pack. a definate upgrade along with a 4PL with an extra Rx for my second car. The 7955 doesn't show 7.4V capable but by what I've read in forums it should be ok.
7955TG Titanium Gears
7945TH
7940TH
7954SH Steel Gears