If they have to remove the plate it doesn't matter if its factory or aftermarket, they cover the same things. My DieselGeek skid plate attaches with fewer bolts that the factory plate. The differance is they are real heavy duty bolts not cheap sheet metal screws like the factory uses.
I think anytime you have a excuse to change out the factory plastic splash shield for a real skid plate it is a good idea. These cars are so low even pulling into a driveway can take out an oil pan. In most cases the DieselGeek pan is cheaper than the factory pan. So why not give your bug some armor.
My photo thread has a couple of pics of a DieselGeek pan on a NB.
Bugmonkey ~ 2005 Platinum Grey TDI