I will have to agree with these guys here. The plane is kinda porky to really take advanage of the Jett 90L, 90LX or a 100LX
Save yourself a few $$ and enjoy the plane for what it is capable of.
What I might suggest is going with a Magnum/ASP 91 XL type of engine (or an actual OS91FX) and adding the Jett turbo-jett muffler to it. The combination will turn the daylights out of a 12x9 or 13x8 prop.... and get you some real nice speed.
The Evo 100 is not a bad engine either. Worth a look. Also the Tower 75 tends to run very well with the turbo-jett and a 12x7 or 12x8 prop.