well i purchased my evo engine at the lhs for 80.00. what a deal, it screams. i have it on a spad trainer and this engine can do what ever i ask it to do, which can be pretty hairy being that i am new to this. every instructor i have had said it is a great eng. i am going to get the .61 size for my spad four star 60 i am building. i may never buy anything else. why change if you find a good thing. i will try taking the baffle out though. hmmmm, more power. what can i do with that.