What type of riding will it be used for? Do you allready have a sonic kit? If not...I can do you one better, I'm a dealer for LA Sleeve...the company that makes the Sonic Kits for CT. They come with a Wossner forged piston w/boost port, CR250 style Boyesen rad valve, top end gasket kit and a new head. I'd have to check my price on them but I think they are $690 and yes I can port them to a 4mil crank. Purchasing it that route will be cheaper than through CT. What pipe, carb, ect do you currently have? Stroker porting starts at $150 and goes up from there based on application. The 4mil crank will cost $190, they retail for $239. A head mod is also required for the stroker application and is $50. There are some other odds and ends parts you will need for the build, hit me up if you'd like a quote.