not really. if the machine is put together properly and setup right, it should be reliable. who did you take it to?
imo you really need to be taking this stuff to someone who SPECIFICALLY deals with banshees, in my experience that is where you will get the best results from.
If it were me, if the crank and bottom end is good I would have the cylinders bored to the next size assuming your not at 66.5 bore, new pistons, cylinders ported for the 4 mil stroke, and have some stroker domes cut for your head.. This should all be done by a site sponsor sir.