The 2200 with the gearing you use now with the 2650, will yield about the same results as just gearing down the 2650. Basically, increasing the length of a motor (as is the case with the 2650 to the 2200), is almost the same as adjusting the optimal range of pinion gears.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy