Unfortunately, neither of the existing nor any of the preceding STC's for the 150/150 engine conversion are aerobatic approved. Again, this aircraft is no longer approved (per FAA Reg's) for aerobatic manuevers. I own an Aerobat, and looked at several 150/150 conversions before I bought my "standard" Aerobat. I spoke with both current STC holders for the 150/150 conversion, and both stated that the 150/150 conversion had not been approved for aerobatic flight. In essence, the aircraft lose that certification due to: the battery being moved to aft of the firewall (150/150's are not approved for spins), and that none of the STC originators were willing to spend the money for the testing. I know of a school that bought a 150/150 to teach aerobatics. They asked an aerobatic instructor to do instructing for them. He read the STC, called the STC holder, and informed the school that they no longer had an aerobatic airplane. As you might imagine, they did not intially accept his word and did extensive research themselves. They even looked at 're-STC'ing" the plane as a potential solution. After substantial effort, they came to the same conclusion - they had a nice 150/150 crusier. I know whoever owns the 150/150 Aerobat may not like this post. However, I wanted to help the group with the results of my research. If the seller asserts that the aircraft is still certificated for aerobatic flight, I would have him send a copy of the STC portion that states that the aircraft still has that certification. By the way, the Aerobat is fun, and if flown correctly, does not need the 150 conversion to complete any Sportsman program.