Radio:
Tower system 3000 w/4 servos US$ 130
Futaba 4YF w/4 servos US$130
Hitec Laser 4 /w 4 servos US$127
Airtronics VG400 w/4servos US $ 135

I would choose the HItec, Futaba or Airtronics (and in that order) (prices are from towerhobbies)

Engine:
I would say a .46 since the buhor is a bit heavier (btw if you are goinf for the buhor scael it down a bit (85%) and will be great!!
GMS $75
Magnum US$ 90
OS LA US$ 65
Stigre US$75

I would go: Supertigre, Magnum, OS, GMS (in that order)
just found the evolution engine US$80 with propeller and pinner (that's a plus!!)
and a Thunder Tiger .42 for US$50.oo (wow!!!) not familiar with the brand though
these las two were on quantum's web site www.quantummodels.com
The fact that you rraadio is 4 cahnnel does not mean it will only be good for your trainer, the radio can last you for the 2nd and 3rd plane as well.