There are other companies out there that make them - but these guys have great prices. I don't know if they are legal in whatever ? that you race. So check with your promoters.
We put one on a CR125 and the diff in power was more than just noticable, the kid is selling his bike now (after a year), and he's taking the PhatHead off and taking it with him LOL The bike pulls much harder with higher compression, but with higher compression you lose a little top - normally. We didn't notice it because the CR125 is ported for about 12billion RPM so it just kept pulling and pulling and pulling. It was the best single thing we did to the bike - that and the new Three Stage Boyesen Rad Valve, which worked wonders. I love intakes, and have tried both big name brands, and both have great spots that they work on certain bikes etc, but the new three stage Rad Valve really really impressedme. If you drop PhatHeadRacing a line, tell them Mikeee said "Hey'.
MP