It is one of the least expensive. I have two friends that blew up 4.6s using the Compucar system. I live about 45 min from their office and was going down to purchase and decided not to . When I buy a kit for the 4.6 in my car, it will be NX with Genx2.
BTW The Charger we talked about is a Vortec, V2 with a 9 lb pulley. I'm supposed to have all the info tomorrow and a phone number for you if still interested.