"i had it installed and now 2 weeks later my car is running like crap,goes into the shop tomorrow to be fixed "
That pretty much answers your question. Anything you do to your car that makes it run like crap definitely has the potential to do harm. Advancing timing has the potential to even break a connecting rod…which can then punch a hole in the side of your block. Pistons and connecting rods don’t like to have the fuel detonated while they’re still trying to compress it. Leaning out the mix has the potential to cause hot cylinders. They can burn holes in pistons or cause preignition, which has the same effect as advancing timing.