You didn't say what you're going to power this with, so I'm assuming a stock 25 size motor with nothing special for speed.

I think you'll find you get diminishing returns when you try to "beef up" a Gremlin. If your goal is to simply have a nice sport flyer, then by all means go to town and experiment. The gremlin is a great starting place for that.

However, the original design was meant to be a "disposeable" entry level low investiment way to get guys into combat. If built stock, it does that very well and you don't have to worry about it coming apart unless you overpower it.

If you keep adding stuff to fix perceived flaws, you end up with a plane that doesn't turn very well, and if you're into combat against other planes, the name of the game is turning quick and weight is your worst enemy.