Save weight = Save Energy, that's Systema's new motto for their new line of AEG internal upgrade parts. The gears are lightened with carbon fiber, the cylinder heads come with interchangeable nozzles, and the piston heads come with two o-rings, one for normal weather and one for cold weather. A lot of thought went into the design of the Energy Line, check em out here at Airsoft GI!
Energy Gears
Energy Head Set
Energy Stainless Bushings

Check out the entire Energy line
HERE!Never before have we offered so much firepower for so little money. The WG CO2 1911 shoots WAY OVER 500 FPS, and since it's non blowback it's extremely gas efficient. This pistol is designed for target shooting only, PLEASE do not play airsoft with this gun!
WG CO2 Pistol

Now on the completely opposite end of the spectrum we have the F-Chu Custom Speed Racer. The FPS is much more reasonable, around 315 or so, but the price is...well, let's just say it's not for the faint-of-heart...
F-Chu!

And while we're on the topic of rate of fire I'd like to introduce you to the Airsoft GI Lipo batteries. We have 11.1v 1600mAh and 3000mAh lipos, and they come complete with a charger, balancer, and liposac:
3000mAh
1600mAh

Finally, of course, the latest in GITV:
http://www.youtube.com/v/myP2dQ0pl7Y&hl=en_US&fs=1&