I didn't have the problems you'vre had so maybe you just got a bad one. The only
problem I had was the elevator bellcrank was pure junk. I replaced it with a MK from
Central Hobbies. I also mounted the engine at the 8 o'clock position so the exhaust
would exit directly under the belly. This took a little time.
I have a SuperTigre Bluehead 60 with a Macs muffler on a Dave Brown glass motor mount
on mine and it balanced right on the money by positioning the battery. I did use a different
tailwheel which required adding a piece of plywood for the mount a little further forward than
the way it came. This probably added a couple of ounces to the tail. I also moved the landing
gear about 3/4 of an inch rearward to clear the Macs muffler. I usually don't use much
of the hardware that comes with any ARF just for my own piece of mind. I probably take more
time than usual to assemble one, reinforcing places and making sure everything is straight.
Haven't had any good weather yet so I don't know how good it will fly but it is very light and
straight so I have high hopes. It looks good.
Sorry you've had problems with yours, hope it all turns out OK.

tommy s