I paid $520 in Calgary for timing belt, balance shaft belts (2), (there might be another one, I can't remember), and water pump. The mechanic says if any of the aforementioned seals were leaking (crankshaft, camshaft, etc) were leaking I would see it externally so we opted to leave them alone. Water pump expected lifespan was about done when I have this service (105,000 miles)

What makes you so sure you need a new O2 sensor?

 

Fouled O2 sensors? Could you be running rich all the time? Worse I've ever gotten in 100% city driving was 520 km with the same engine.

 

With all the crap I read about the balance shaft seals letting go, I made sure to replace all of the seals while I was in there. For a pro, it probably won't add too much to the cost, since they're down that far anyway.

Since the coolant is being partially drained anyway, now is a good time to do the thermostat and coolant flush.

But a basic t-belt job should be the belt, balance shaft belt, water pump, tensioners (if a lot of miles), valve cover seals and drive belts at minimum.