I'm not a big Haro expert, but from the Haros I owned the difference is in the composition. The higher the model - the better the components it uses. Other then that it's similar in its frame and geometry.
ok now..meaning if an X1 has upgraded parts as the X7..technically its already an X7?..haha
Here is a project I have been working on just because.....well I had the time and I could. Enjoy
Clearance for the rear wheel is no problem.
I used a 26" Fox 125R Fork because I already had it and I didn't want to buy a 27.5 fork yet. It has about 3/8" clearance to the tire. It is not recommended as it will pack up with mud and other stuff. It will serve my experimental purposes.
Here's my Shift R1 after another round of upgrades. I installed a new Raidon fork and a pair of Brakeco 203 mm rotors for my Hayes Trail Stroker hydraulic brakes. After I pick up some new tires, I'm going to stop upgrading and just focus on riding and developing better technique. It's as good as it's going to be.
I think I might like this better than my 07 Anthem 0. Its heavily upgraded, and it is so efficient. I a very impressed. I guess my days of riding The Haro Master, and Mirra Flair were a little foresight of the future of Haro.