Hi!
Being a pylonracer fan for more years I can remember I like speed! But being a racer I also know that light weight is very important! This is something newbies tend to forget!
So powering a plane with enought power without sacrefying light weight (low wing loading) is what's counts!! What's enough power you learn from experience! Having lot's of power and a heavy plane is no good! Could get you into more trouble... The saying: "I like to overpowering (bigger engine) my planes as this could help me out if I get inte trouble" is just a tale...Nothing could be further from the truth as more power usually gets you into trouble more easily! And newbies cannot throttle down or up...fast enough to save a plane, that's my experience.

If you go the .90 size path remember that APC props are always outperforming MA white tipped props and that 13x8 or 14x6 props are good choices for a .90 four or two stroke.