The PT-40 would make a great first kit and first plane as would the Sig LT-40 (probably does not matter much as to which one they are very similar) If the engine has been kept clean all these years it should run fine. I would run a couple of take through it on the ground just to make sure all the cob webs are out of it. As for Bushed engines not lasting long I have a OS 40 FP that is about 20 years that has had many many gallons of fuel ran through it and is still running. Whether a engine has bushings or bearings would have nothing to do with a engine loosing compression.