The differences are rust and cost. Being where you are, the only rust you might see is from the water by-product from the CAT, and that shouldn't take much if any life off of the system. SS will look nice, but is the extra cost worth what isn't seen 99.9% of the time. If you lived in the NE and planned on keeping the car for a long time, I would think the SS would be a heavy contender. My choice is the aluminized.