The Seagul Extra 300 75 sizes are a bit of a handfull. I had one with an OS .91fx and a 15x4w APC. It was a balistic missile but put it into too tight of a turn and it would snap and go into a spin. This is not bad but it is realistic. a .90 sized two stroke is a lot of fun in that plane but far more than it needs. If the weight penalty from a .75 two a .91 is negligable (withing an ounce or two on a plane this size) then go for it.

Just remember this plane is not going to be your relaxing Sunday flier. It will take skill and concentration. Should you get into a snap/spin with this plane resist the urge to pull back on the elevator. Let the controls neutralize and add power until it starts flying straight (usually straight down so I hope you have altitude). The ease back on the elevator and regain composure. I sold my Seagull Extra to a club member who lost it from a 200 ft snap and a panicked full up elevator death grip. This reaction while natural is wrong and lead to a 200 ft spiral of death. Properly managed the plane could have been recovered in about 40ft of altitude loss.