At MYERS dealership.
the reason your glow plug is less expensive is because your car has the small engine. The one I drive the plug itself is about $80 before tax at the dealer.
and for the labor at MYERS, the diesel tech is about 20$ extra per hour comparing to the regular tech which is about 90-100/h.
By the way, dealer will always rip people off for sure.
Since you have mentioned Myers VW, I will assume you have a VW. VW offers couple diesel vehicles which are TDI golf, TDI Jetta, TDI Passat and TDI Tourage(in Canada).
The glow plugs for TDI golf, TDI Jetta, TDI Passat are same price(same part #). At VW dealership, the retail cost is less than $15/each.The glow plugs for TDI Tourage is less than $40/each. I have no idea where you get the price of $80/each for glow plug for VW.
The other thing that you have mentioned is the labor rate at Myers. I personally don't know about Myer's labor rate, but 2 other VW dealership in Ottawa will not charge you extra labor for the difference of engine(as a matter of fact, I work for one of them).
The last thing you mentioned is "dealership will always rip people off". Most dealership that I have dealt with use a industry guide line(mitchell on demand) for labor that they charge - which means, if mitchell on demand quote the Job for 2 hours, that's what they will quote you. If you have been ripped off by some dealership, I can only fell sorry for you.
The other thing you should know that VW have launched a recall and warranty extension for Glow plugs for MK4 (4th generation golf, Jetta), certain passat and Tourage in the winter of 2010. If you have replaced your glow plugs prior to that, contact VW customer care with receipt, they will gladly refund your money.
There are a lot of reason to go to dealership. One of them is you never know whether your car still have warranty or not. The manufacture will release new warranty extensions and recall at times, at your local garage, they won't have that kind of info(even if they have, they can't repair it under warranty, they will charge you instead). For example, VW has release warranty extension for Glow plugs as I mentioned earlier, they also release warranty extension for Camshaft (cost about $2000 to $3000 for retail) for certain BPY engine (2.0 turbo FSI engine) due to camshaft follower and high pressure pump failure.