I would say go w/ the stock crank, and the Jiangwayne 50mm kit. Cheap, and very strong. I had a delay in San Fran. customs, and received my jug yesterday, (14 days). Sooo My experience is limited to a good breakin, and 4-5 miles wide open. Buttt, The jug is flawless. The ports are even, and symmetrical. The piston sits 2mm above the openings at bdc (to allow for the stroker crank) but the squish is perfect at .8mm. The dome has a 40% squish band that will tolerate regular fuel, but it screams on hi-test.There is a 28mm exhaust that works for all the standard pipes. (next r /rs ect...) The only "fitting" needed was in the piston casting. The boost port had some xtra metal in the triangle cut out, and the skirt had the same. My last runs w/ the 70cc malossi were at 60-62mph. The new kit w/24 mm Delorto is burying the speedo on flat ground. The mid range is the BIG winner. It will pull the front wheel leaning into a corner. My overall opinion is I NEED a stiffener on the frame. This has gone from a cool scoot to a scary ass machine. I know this is what this scoot was lacking. On to the stretch. You can pull off the center stand, Remove the rubber bushing from the forward engine brace, and couple a 10" pipe into the bushing housing. Then re-bolt the engine into the holes from the center stand. That gives you a 6" extension for free. No welding either as the pipe is held in place by the engine mount. Look at it close, and you can have the job done in an hour! I will post some picts. of the finished scoot tomorrow. Peace~