I really don't know if that rockshox fork is really much better than the suntours to justify the extra cash. What you could do is buy one of the cheaper bikes if you are happy with the rest of the components. Ride it for awhile till the fork starts holding you back and then upgrade it. Suntour has a nice upgrade program and you can upgrade to one of their air forks which are actually fairly good for around $200 last time I looked.