Hi Zac
If you go to this link there are fdr charts for the 416, the 416 has the same final drive ratio as the v2.
Remember the V2 has .6 module gear pitch not the 48 or 64 as in the charts, but you will still be able to get the correct pinion size.
The kit spur is 70T so a 32T pinion will give you a 4.50 FDR.
h**p://rss.rcmart.com/2008/12/31/tamiya-trf416-gear-ratio-list/
The set of pinions from tower hobbies you are looking at is 48 pitch these will not work with the kit spur.
This pinion is the correct 0.6 pitch.
h**p://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXUFL0&P=**Missing%20Data**
I hope this all makes sense!