The increase in range is NOT directly proportional to the increase in FPS, i.e., if you double your FPS you will NOT double your range. Guns do not achieve longer ranges purely with higher velocities: all projectiles (airsoft or otherwise) are subject to ballistics. In order to be able to pull off anything remotely ballistic in airsoft, you need accuracy and shot-to-shot consistency. The extra 30 ft you get from higher velocities isn't making that big a difference -- not to mention that just because your shot can get out to a given range doesn't mean you can consistently hit a given target at that range.
There are stock TM guns that have no trouble keeping up with lightly upgraded guns.