Finally got to try the packs out today in my XXX-S. WOWSERS!! There was so much more power than the packs I have been running, I was fishtailing like crazy for the first half of the race until I figured out how to "harness" the extra boost/speed and keep my car straight. My pitmate was experiencing the same thing. Crazy punch! Awesome batts guys, will be getting more cells in the future for sure