I have now put the o2 sensor in form the other engine. It's giving me a #48 code now but the #41 is gone.
I set the timing with my grandpas ancient light (that was a pain because the light was intermitent)
The engine runs fast sometimes but overall, it is slower. It has started to "hunt" at low RPMs now. I really didn't want to spend $300+ for a new o2 sensor.

I drive at work for the next 5 days so I'll get more feedback from the car tonight.

I had the spark plug problem with some split fires I put in like 7 years ago. they worked at first and then ran shitty like dEfused described. I took it to the dealer and spent a bunch of money just to find that split fires dont work in a honda. I've used NGK ever since. They don't last as long as others but they run great.