ORIGINAL: bassman
Now that I think of it I had Jtek make a pitts muffler for a vertical installation of GMS 25 in a 1/12 scale warbird. That would be perfect for this. It probably won't be built anytime soon but when it is I will certainly send pictures along.
Bassman
How about an electric conversion???? I have the cedarhobies kit and am doing an electric conversion on it. I have E-flite Power 10's for it which can pull up to 12 pounds(total of the 4 engines). Since mine is electric, the weight will be a lot less then what is reported on CedarHobbies website when using 4 x .32 OS or Magnum glow engines...coincidentally, the weight was 12 pounds.

So, I'll have plenty of left over power.
I also will be doing internal elevator servos, scale nose blister, nose windows, cheak guns, top turret guns, ball turret w/guns, chin turret, cheyenne tail gun, waist guns. Most of those mentioned are not provided in the kit. By the way, if anyone wants to know, the scale size of this plane is 1/16th.
I will also be modifying the cowls to look more scale, adding in radial dummy engines(thanx to Twinman), retractable tail gear and retracts if I can fit them somehow.
The plane is undergoing a complete skin recovering in aluminum tape.
The first pic is the scheme I am modeling after.
The second pic is with the canopy area recovered in aluminum foil tape(but have not added in any panel detailing like rivits yet). The peices are set on the original fuse just to show what they look like. The windows have also been redone and reshaped to better match scale appearance. I still have a lot to work on though as it takes time. One layer at a time if you know what I mean.