Mine has a YS .91FS Air Chamber. Power of some 1.20s and 1/2lb lighter. I swing a 16X6 with 20/20 fuel and have gobs of power. I didn't even try to build light and can only imagine if I had! If I did another one, I'd carve a lot of ply out and use lighter servos. You can stuff a huge engine in if you want, but the wing loading goes way up and it doesn't have the 3-D abilities if it were lighter.
My 2cents