These are the common problems on most the S2K. Tranny buzzing while on deceleration happens to all S2K, I think. Vibrations in the rear end, you might want to re-torque the rear differential bolt. Use the Search feature. I've read about it somewhere on here. Notchy shifting into 2nd, take it up pass 3k RPM should solve that problem. At 3k+ RPM is when the syncro is really at its most sufficient or shift to 2nd really slow. But I've read about some nasty stories about 2nd gear on AP1 so I am unsure if that would fix that problem. Best of luck and congrats!

Jason