After much feedback, all very positive, I decided to move forward with Concept 1A, much as I liked them all I felt this was nicer balance. I really liked black bar front, not so much back, opposite for color coded version (and Greg Weld liked it best

). But I will seriously consider doing 3 different sets of bumpers to trial on car when the time comes.
Had Ben do another update, put Grip Rebel rims on Concept 1, pulled Z28 stripes back to factory position, moved vents forward, color coded door handles, so this is now "final" rendering.
Ben has been great to work with, highly recommend him to anyone thinking of getting a rendering done