Good Idea if you have a need for speed. Remember scale speed and that the Brown JR wasn't flying at 500mph like the Rare Bear and such like.
The G-45 is smaller and a little heaver and way more power, the Brison 2.4 is in between weight and power wise. Don't forget a FPE 2.4 also.
Search around RCU I think Aero Bob has a 40cc and 50cc compairson chart with REAL weights.