This is a direct swap for a 97/98 Mark VIII, the GMS 4V connecter kit with new silicone boots and stainless steel connecters (wires). My old plugs which were the stock ones were in bad shape after 63k miles and 8 years. I noticed better throttle response right away but I don't know how much it was from the GMS kit and how much was it from the new plugs. The car will now chirp the tires in drive on the 1-2 shift which it never did before. If you have a Gen 2 I would get this kit and install it with new plugs... I got my set from Modular Depot but you can get it directly from GMS as well.