I was hoping you would come in and tell me/us what the actual differences are. I understand your one word answer is in responce to my question about the availability of a "stoker kit". However, I would have hoped for a more detailed explaination from you pointing out the differences and correcting or confirming my theories. Unfortunately it is imposible to know exactly what your tone is on the subject but it's imediate apearence is that your offended by my comments and do not want to expound upon the benifits of upgrading to the 40-GX as oposed to modifying a 35-GT. I do thank you though for making my decision easier to just make the move to 50cc aircraft and engines and leave these "betweener" engines alone. I will note however that I was happy with the overall quality and reliability of my Evolution gas engine but it will be sold now to fund the purchace of a DA-50.