RE: P51 PTS or Arrow trainer
I taught a student on the PTS this summer. All the talk about the weak landing gear, poor fit of the low speed mixture adjustment in the cowl, bad handling with all the trainer aids are all true. Having said that, he learned to fly. I think he would have learned quicker and spent less time repairing a good high wing trainer. I second the suggestion that the Hanger 9 P-51 is a good second plane.
The student I taught on the PTS built a Spad Debonair after he learned to fly the PTS. Guess which plane he has more fun flying now? The SPAD. Its more durable, handles very well (no dihedral wing), and was cheap to build. He's learning more flying the SPAD because he's not worried about it.
Brad