Okay, I'll save some people some time. After chasing this down I'll give an abbreviated account of what was discovered since I'm typin on my iPhone right now

1. Took it to the dealer - they diagnosed it as a leaky manifold gasket; wouldn't tell me which one but I was quoted $1,800 CAD + tax to fix it. After picking myself up off of the floor I didn't ask questions, I got it out of there and took it to an independant BMW specialist shop.

2. They diagnosed it as, get this, a STUCK OPEN THERMOSTAT and a failed MAF SENSOR!!! They changed both, at a considerale cost as well mind you ($1,200 CAD + tax) but I was shocked that their diagnosis was correct and solved the problem.

I've learned my lesson about BMW mechanics, and am now in the market for a newer X3, X5 or GLK 350 WITH EXTENDED WARRANTY.

Seriously, I thought it was only the paranoid people who suggested extended warranties and to be honest I never subscribed to that camp but in the case of aged German vehicles it is imperitive.

Hope this helps some people; iv been chasing this down for 2 months and I'm so done.