Changing a script is sometimes easy and sometimes a nightmare, depending on what you're changing from and to.
If you get something from a company with a scalable script (i.e. several versions, from cheaper to more expensive) it's usually a lot less hassle than changing scripts to upgrade to a more powerful version from the same company.
Since the X Power Links team has just admitted that there will probably never be an update to the script I will no longer recommend that to anyone, but I'm working on something for myself since they've dropped the ball. If you're not in too much of a hurry (i.e. you can wait 6 or 8 months) I'll be releasing the "Lite" version of my script, and I assure you that upgrading from one version to the more robust versions will be painless. If you're in a hurry, I believe Gossamer Threads is well liked by many and there are several versions of that at different price points