we dont charge by the mitchell system, but my estimates are given by experience an what i know or REASONABLY estimate takes to get the job done.

I know what it takes to do swaps, turbo kit installs, suspension, etc. I try to stick to my estimate as much as i can within reason.

Custom stuff, is up fro grabs. Our Custom fab rate is $75/hour an its done when its done. Like this 2JZ RX7 we are doing, i budgeted 30 hours , but if we go over that, ill be calling the guy an telling him its gonna take more. since ihave never done a job of that caliber, i cant give an accurate estimate.