Yeah they work. I have never tried them. It takes alot of time to do the porting job its not a 15 minute job theres alot to doing it. look on Youtube for a porting video think theres one on there shows race logic temp plates. Theres alot of prep work and alot of grinding. It takes hours to do just one. Now your doing 3. If you want a summer project go for it. All honesty they ZRTs ran really well stock. Getting the power to the ground is where I would lean more. More studs, clutch and jetting. Alot more bang for the buck.