heliguy, i just found the build plans to the x-cell, will post back with manufactured date, thanks for the insight on the tsk, but i got a deal could not pass up, think its the mystar, carbon stacked frames, servo tray, jr pro head, cnc machined swashpale, ys91 with 2 9202, and 2 jr nh 537, new clutch, main gear, bell housing, purple andonized parts etc. etc...upgrades, i did check around before buying, several guys still carry parts, could not pass up for 200.00 need tail boom, and air chamber for ys91, in your opinion, should i still have passed it up, i guess still wanted a heli like the guys at the park. but back to my current x-cell project, it has the aluminum u-shaped muffler, what can i put for replacement or is the one i have still okay, again thanks for all your help, have you ever been to ama convention with cars, boats, air, helis, swapmeet, etc.. i am going this saturday in pasadena, calif, to see if any good deals, like gyros, electronics...