A straight opener swap is within reach for a handy homeowner, and we won't pretend otherwise. The honest limitation is in the details: getting the mounting bracket onto a 2002-era rafter at the right height, squaring the rail, and getting the two safety sensors to actually agree with each other is fussier than the box makes it look. Get the sensor alignment wrong and the door will reverse itself for no obvious reason, or refuse to close at all.
The bigger risk is horsepower. If your door is a heavier insulated double - common in this part of the service area - and you install an opener sized for a lighter single door, you'll burn out the motor inside a year or two, sometimes sooner. We'd rather tell you that up front than sell you a unit that's wrong for the door.
We also don't fix the door itself as part of an opener call - if the door is the actual problem, sagging panels, broken rollers, a spring that's gone, that's a separate job. See garage door repair for that side of things.