RE: 4* kit?
I have an LT-4o and two 4*40's. I cracked one of the 4*'s up due to a bad aileron cable (honest!).
I can't say more than what the other folks have said here about how much fun the plane is, and I fly mine on a TT Pro 40, just for the record.
My suggestion would be to hang on to the LT-40. If you can't fly during the winter, or for extended spells, it's nice to haul out that LT-40 and run it around the pasture a few times, just to get over dumb thumbs.
I agree with everyone that says that the 4*40 is a great 2nd plane, and a lot of fun to fly, but it IS quicker than an LT-40. I'd keep that LT-40 in the stable too for those time when you want to just bore holes in the sky, or when you need to refresh your thumb's memory!
Just my $.02