RE: "slasher" versus spad
I would say the double stick foam tape is your problem. Its not thick enough. Get some 1/4" or 1/2" foam rubber under the tank. Those Mac pipes help a bit on power but don't have the tuning of a mouse can. Also your planes are heavy this will make for a tough launch. My avengers usually weigh in at 2lbs 14ounces.
Scott Stringham