Yeah the ATI comes with a 9", but if you spoke to them over the phone, they would build you any converter you wanted to fit their 7m or JZ kit. They built the kit for the destroked HKS MKIII racecar that had a glide in it as well as did the converters for Paul Efantis's old race car. They are Selling you a 9" because that is an excellent size for these cars. The converter needs to be matched to the engine/car. It's not like an 11" converter is better than a 10" just because one is bigger, they have to be matched properly. The ATI fuel and blown can be had for 850 from summit and usually substantially cheaper in the fall getting close to the holidays. There isn't much that rivals this converter except for a Chance at 3x the cost.