29arod, I'm glad you brought up this subject because I'm in the process of setting up my 30 coupe. I think the only way to go is the under floor mount, for two reasons. First, there isn't any room to put it under the dash without a major headache from what I've seen on mine. Second, I've been to shows where guys have used the underdash mounts and there is usually a booster and master cylinder hanging on the firewall. This is ugly and takes away from the looks of your motor. When you open that hood you want eyes to focus on the motor and not the booster/mc assembly. There are several manufacturers of the underfloor assemblies and the pricing is pretty reasonable. Running the brake lines and brake light wiring should be a snap too.