If you want some more H.P and have alot of miles on your original engine. Try to get a 2.0,2.5,or 2.7 from the 99+ Vitara, Grand Vitara or XL-7 They all fit with a little work.
I know that the X-90 has alot of the same parts as the Sidekick/Tracker. Check out
www.calmini.com