HP....I've installed one on My TR-21 and I'm sure installation would be the same for your Nitro....Very easy to do....Got a friend thats a Dealer Rep for them if ya need to purchase or need some tech tips...As with any Fiberglass cutting, cover the area with Masking tape first. Use a cordless drill in reverse with hole saw to start the hole, then switch it in forward... I've found that this helps to keep the Gel from chipping....Get a GOOD Pipe cutter or Cutting wheel on a grinder to cut the Stainless Pipe once measured correctly(this is the hardest part as that stuff is TUFF ta cut through!)...If ya need any help gimme a holler... I even took step by step pics of my install but it's alot of pics...Could possibly send some of them to you if needed ;-)