I'm not sure how you'd get it out without removing the turbo as I don't think there's any way to wiggle it out underneath. Removing the turbo is SO much easier than trying to fight it out underneath anyway and at MOST all you need is the $10 turbo gasket kit. You have an 03 so it's a LOT easier than the later models IMHO. If you're replacing the y-pipe because of a broken flex bellows on the passenger side then that can be done without removing the turbo but it's still a PITA.
From what I'm reading all I see him removing is the up-pipe not the whole y-pipe assy. Nothing at all like removing the complete y-pipe. I'm not saying it can't be done, it's just a LOT easier to remove the turbo to get it out and probably a lot less time in the long run. It only takes about 30 minutes to remove a turbo (with a little practice).