Turbo systems have made the Evo tuner world what it is today. The ask is which Evo Turbo for the Evo X gives the best bang for the boost. The three main contenders are street Assassin, Forced Performance, and Garret. The street Assassin 50 is the easy, bolt on Evo Turbo. After this relatively quick install, you should expect about a 150 hp gain and high eleven's on the track.
Fp puts a gift under your tree with either the Red or Green Evo Turbo. Just like the street Assissn 50, the Fp Green is a bolt up unit that looks practically entirely stock. It gives a shorter spool for quicker power, but can't match the Red for max horses. The Fp Red turbo will get you close to 500hp and high ten's on the quarter mile. Although, you might be disappointed with the lag and might need to compensate with some cam work
Garret by far has the most collection to offer, although the cost is more decisions, more confusion, and more money. The models for the Evo X contain the Gt30R, Gt35R, and the Gt37R. Don't let the alphabet soup become overwhelming. The numbers correspond to the frame size of the inducer on the exhaust. Essentially, as this gets bigger, there is more possible power, but more lag. This is seen when comparing the Gt35R with the Gt37R. One blogger claims that the Gt37R makes 75 more hp than the Gt35R, giving more than 700 whp. The downside is that the Gt37R takes longer to spool to give that power.