It's your choice whether you want to use sea foam, there are many Hondas and other makes out there they just survive from regular maintenance and oil changes. Most shops will try an oil change first (easy, relatively cheap, and may remedy it).

Not all oils are created equal; however, most quality oils that meet or exceed certain standards are comparable. Newer oils are not the same as oils previously sold years back.

If the cost for "high mileage" oil is the same, then it doesn't hurt to use that. High mileage oils generally have more detergents, etc. For example, at Walmart, Mobil 1 high mileage synthetic is the same price or close in price to regular Mobil 1 synthetic. You don't need to use synthetic though; although I use it.

Motor Oil Grades and Service Ratings

So I changed the oil using Mobil 1 and Mobil 1 filter. Cleared the Vtec code but the P0420 Catalyst Efficiency Below Threshold Bank 1 is still kicking out. Guy at AA said that when it was hesitating that the efficiency was thrown off, but running it and letting the converter heat up a few times may clear it out.

Does this sound reasonable or should I just replace the converter?

If the car is running ok, then I would wait. Honda catalytic converters are pretty solid and really expensive. I never had any experience with aftermarket converters.

If it were my car, I would wait to see if the code clears up. There is a video on the P0420 code on YouTube by scotty klimer (sp?). He uses lacquer thinner in the gas tank to get rid of the cat. He also suggests soaking the catalytic converter in soapy water overnight. It is worth your time to watch.

You may want to search for cataclean on here. One member had some success with that.

Oh yeah, the car runs great! Best it has run in a long time, just hope it's not going to become too dependent on that high dollar oil! Hahaha

I found a bolt on replacement at AA for $150. But I'm going to run it a bit and see if I can't get it to clear.

Thanks for all your help!