OS 160 with Bison Pitts is perfect. It provides the exact right amount of weight you need in the nose to balance correctly. If you opened up your stab and beefed it up, you won't have any problems. Just remember to add wing bolts too. The stock setup with the screws starts to wear and the wings get loose.

I have been flying mine for over a year and have no problems. It screams with the OS 160.