...well...we have built a few GT1 cars over the years as well...I just can't afford to race one....

...They are typically pretty simple...more simple, more better...
My stock dash is LITTERALLY a shell however....it weighs NOTHING...there is nothing under the cheap light plastic...I did it for asthetic reasons.....my fabricator was PISSED I did not go to a dash like you want...at the time I wanted the car to look more stock like for ITE rule puposes...
That is what I am doing right now to the front of my car...making it more GT1 like while not losing the stock frame and its ITE eligability....GT1 on the cheap...