If the planform of the wing is reasonably close to original... should be no problems using it as a primary trainer.

The semi-symetrical airfoil will give marginally less lift at the same angle of attack and airspeed when compared with the flat bottom wing (assuming same chord % max thickness...) The main place there will be a difference, and probably the only place it would be noticed is in the improved inverted flight performance.

Compare the performance of The "Avistar (semi symetrical) with the Tower Trainer .40. Both are about the same planform, about the same weight. The only major difference is the airfoil. The only major performance dfference is in the inverted flight being better with the Avistar. I expect you'll find the same to be true of your larger aircraft.

It aint broke. Don't fix it.

I agree with fhhuber. It will give you better aerobatic flight, and it will take the wind a bit better. Don't worry about it being heavy. If it flys fine, forget it. I saw a giant scale Spitfire that weight VS size was a flying brick, but it actually flew VERY well, and would land much slower than scale. Some planes feel heavy and fly light, others feel light and fly heavy. Plus the heavyer they are, they generally fly better in the wind than a light plane.

Avistar balloons just as much as the Tower Trainer... if you try to land with too much airspeed, the plane will balloon when you flair for touchdown. The prevention is to slow down.

Heck... the biggest complaint I hear about the 4*40 is it likes to float on past the runway... with a FULLY symetrical wing. Slow it down... it lands just fine.