new spark plugs needed? nitrous...

Change them! Ive been running nitrous for a while, and it wouldnt hurt to put in the HT0's. They are only one step colder, and have no affect on daily driving. Be sure to start off small, and work your way up on the jets. I wouldnt go over a 100 shot with 93octane...IMO. Some timing will need to be pulled for the 125 and 150 shot, better fuel wouldnt hurt either.

I check my plugs often,good habit to get into, simple to do as well.

Remember...consistent & optimum pressure is the key.