There is a big differance in dome design, the squish angle the step and chamber design all play a huge part in the domes. I have not seen a trinity head and I dont know any one who makes domes for them other than trinity. But the noss uses the same dome as the pro-design and (imo) there is a better chance to find a better dome design with more people making them. The dome plays a huge part in the 2 stroke, not to knock trinity its just my observation.