Hands down the SMC shorty pack. This past weekend I switched out from PROTEK 100C 7000 to an SMC 4600 70C and added the weight difference to the car and it was 2 tenths quicker consistently. I think this may be due to the weight being lower CG. I oddly had more punch than the PROTEK and no fade for all the triple A-mains. Finished 2nd though but the Peak and Reedy shortys had much less punchy feel. All were new with less than 5 cycles before the weekend. This was in a 17.5 blinky setup.