Agreed, buy quality, the radio will be with you for a lot of years so get the best you can afford. I tell my students to never buy anything until after they solo and have a good idea if they will stay in the hobby for a long time. Most club instructors have a good radio and buddy box so there is no reason for a student to buy anything except there own fuel, the instructor will tell you what brand to buy if your using his trainer and engine.
The Cub is a nice plane but like everyone else said, it isn't a good trainer at all. Last one I built was the anniversary Cub like yours. They don't lend themselves to mods for the most part but your plans will show you the clipped wing version if you want one that is more of a stunt plane. I used an OS 91 four stroke on the last one. I built it for a friend and that was the smallest engine he had for it. It is also used as a float plane. In flight it never gets more then 1/4 power. Any good .46 two stroke is just fine with the plane.
The plane comes out tail heavy so during the build lighten up everything aft of the CG. In my case the big four stroke helped out a lot with that problem. A .60 is over kill but in the future that .60 will be used a lot more then a .46.
ASP, I haven't used one so I don't really know, no one I know has one in a two stroke but there are a lot of Magnums in my area. You either get a good one or you don't, I have seen them total junk out of the box and I have seen some that were very good? If I was buying new I would go with OS just because they are pretty much good right out of the box and user friendly for a new pilot. They also last a lot longer.
Buy the best you can afford and you won't go wrong, buy cheap and it will come back and bit you in the butt. I use Futaba and Hitec, most the people I fly with use JR and Spektrum. It's just one of those choice things but I like the programming in Futaba so that's what I use.