Hi Gene,
The 4*120 is a lot bigger than the 4*60. It can weigh up to 12 lbs. and has an 81" wingspan. We have one in our club and it make the 60 look small. I'd like to have the bigger one to put possibly the M V V S 1.6 gasser on (Evolution engine now) so I can add a smoke system to it. That engine should give it almost unlimited vertical I would think, and with the smoke on should look cool!!