The automatic transmission in the Bronco is actually built well. I've noticed that they don't like wet or corroded connections. That seems to be the quickest culprit with shifting issues. To be honest, when I got mine I had to replace the front seal from a result of a throttle position sensor failure. When I removed the transmission and transfer case, I took notice of just how BEEFY everything is built on these rigs. Especially when compared to my past Jeeps, there is nothing light duty on a Bronco. The rear diff is certainly no Dana 35 As for the LSD, I am honestly unsure because I have never checked. Maybe someone else can chime in here and help me out. IIRC, it's an open 8.8 but don't hold me to that at all. As for bolt-ons, are you referring to the engine? If so, the response per dollar will not be significant enough to justify, IMO. However, I just can't deny that a Flowmaster sounds great on these. I love mine.