RE: New engine
The LT 25 is a high wing and a nice flying trainer. The 25 will work well for a trainer but will not be overpowered. I have flown this plane with a OS 20 FS which worked but very under powered. I have also flown it with a good 40 2 stroke and it is no longer a good trainer at that level.
Like all of the Sig trainers you would like this plane......I sure do.