So with all that said, if it’s what you want to do, all the power to you. I understand and even like it and you'll do it well. But at the high risk of hijacking your thread (apologies in advance, I realize it's your photos post, so delete my remarks at will), seems like the two issues discussed in the later remarks are aerodynamic flow and cooling.
I just don’t think I can agree the mod you describe will provide some measurable functional improvement in a street car and would even question it for anything except extreme competition. So, the first thing I’d have to ask is what’s the purpose of the car? (I know; fun! But..) Is it an open road race car or a street car? The air dam design and its ground clearance will drastically affect under car flow compared to the comparatively modest amount of air you’ll get through the radiator, fan, etc., and unless we’re talking very high speeds and competition where the minutia matters. I just don’t think this volume of air and belly pans are material compared to other factors. But IMO, they do look great.
After an effective air dam, the other factors that cause nose lift at speed such as the shape of the Pantera in general, the configuration of the nose, and especially the and rake of the car, are orders of magnitude larger factors than the contribution from the volume of air you can deliver under the car through the cooling system. If you have a different view, happy to hear it.
I also see a lot of people performing hood mods for the purpose of addressing cooling issues and simply put, it takes radical mods to make any measurable improvement in this regard and rarely if ever (never in the case of the small grilles) do they address low speed cooling issues. OK fellas, have at me.
Kelly