I've been fixing up an old XJ and I was struggling to keep speed up in the mountains on the way to snowboarding. I decided to add this prior to a larger throttle body. I was pretty skeptical at first, but I dropped it in with about 20-30 min of work. Like some people mentioned, the holes don't line up perfectly, but it's not hard to bend it into the right spot. I was pleasantly surprised with a decent pickup from stop and I can feel there is more power. The Jeep format shift into lower gears as often. Haven't taken it to the hills yet or been able to check gas mileage, but at this point, I wouldn't take it off.