3g hemi gas mileage

The cats are a no go!! The TTI headers and exhaust just dont allow any room for the converters and I cant see cutting up a 750 dollar exhaust for 200 dollar converters. On the upside, I found a place that has a chassis dyno and can tune the factory efi setup. They will do base runs, get rwhp and rwtq, start tuning, more dyno time, more tuning all for 400 bucks. When is my tax refund gonna be here??