if you want a good kit at $150, check out the single piece head/jug kits on amazon. amazing power!!! i swear by them. guys spend gob's of money buying parts these ugly little motors put on from the box. so far the one si have are all better then even the pk-80 kits. more torque, and more rpm's right from the get go. an after break in, wow!!! with my 36th sprocket i still run up hills fast and hit speeds far faster then i feel safe riding at. i keep a 40th sprocket on now because i get froggy and need to keep my self under 40. lol. with the 44 supplied in the kit, i was popping wheelies and spinning the tires. i could climb tree's with a 44. with my 40 tooth i hit a top speed of 37mph. i prefer to stay at 25. out of the box every single one of my single piece jug/head combo's were pulling 8500 to 9000 rpm's!! best part is no head gasket to blow, bad thing is not as customizable . but i don't care with the power they make. an ik guys spend gob's on parts for other engines, i was and kinda still am one of those guys. i have probably 6 motors laying around at different stages in build. i don't sell these, i play with them. i'm a motor addict and this hobby is one i can afford. i have about $9,000 into this hobby in the last idk how many years. i've killed a few and made most sing. spending money doesn;t make these go faster, knowing the gears and tuning them right and the proper mod's done by hand , does. a dremel will be your friend in this new adventure of yours. just remember, baby steps when porting and matching. baby steps so you don't ruin the jug.