I had both Jammin engines .21 in my buggy & .28 in my truggy... They have great power/speed BUT the run time sux and theres no way in hell the .21 is faster/more power then the extech .21..!!! Heck I also had the Picco P3 .28 FT in my truggy it's nice to have the power for the sort run-up's but the extech's have the same low-end. In the end the extech took me every time due to run time/pits...
My back-up $174.00 Sportwerks .21 V2 engine will smoke the Jammin engines anywhere on the track & fuel mileage too! No B.S!!!