Go for the kit with the new stud is my advice. If the car has had a previous belt change there's no guarantee that it wasn't overtightened which can weaken it.

I'm a bit perplexed by your mention of 'idler bearing' though ! Do you mean the actual tensioner as the AUD engine only has a tensioner ? I've only fitted genuine VW belt kits to these and all the tensioners have a new bolt which is press fitted and can't easily be removed.

Double check the engine code or the belt kit(s) to make sure it's correct first.

My thoughts on cambelts are always use the best quality and most complete kit you can get or afford.

If you don't want to go the genuine parts route, use something like Gates or Conti kit. With the pump, make sure its got a metal impeller wheel as the ones with a plastic wheel can crack on the spindle with obvious results. Ironically, the genuine VW pumps have a plastic impeller so usually, an aftermarket pump is better.

So, in short, get the best quality kit and pump you can and follow the fitting instructions closely especially the tension of the belt and torque setting of the tensioner bolt and you can't go far wrong.