heat shield rusted on over 02 sensor

I have already replaced 2 of the 4 O2 sensors on my 2001 Nissan Maxima, and a third one is bad. I have the part, except I can't get to it without removing the heat shield. The heat shield is apperently rusted on, or the screws seem to have "melted". I am ready to sell the car (possibly trade in at the dealer) and don't want the check engine light on. Dealer will already be low-balling me on the trade-in (165K miles Maxima SE 5-spd).

Is there a way to cut away part of the heat shield, bend it out of the way to change the sensor, then bend it back in place without causing too many problems?

Thanks.

 

Have you tried soaking it in WD40 or similar?

An exhaust shop can take that heatshield off in a matter of minutes for cheap. It will probably need some heat from a torch.