Thanks, yes my 12 is IBM. NO visual issues so far with the 4" cowl. I will take a pic of my interior and post it. Changed all my gauges last year and went digital. Figured my car was too modded for stock type gauges even though 2 years earlier i had put new stock gauges.
2012: Vmax TBody, CAI w/scoop, Solo HFC, ZL1 FP, Magnaflow TruX, Dynomax VT, RX catch can, HP Tune, BMR; Springs, Sways, Trailing Arms, Toe Ends, & Safety Loop, Koni str.t, Pioneer Z150bh, Phoenix Gold Sub, Hertz speakers & 5ch Amp, SS rear with 3.91 gears w/Eaton TrueTrac, and BMR bushings, Baer Decela Rotors, Goodridge brake lines, Brembo(GM) 4 piston calipers, Hawk Ceramic pads, and Vredestein Ultrac Sessanta Tires, Ny-Trex Nitrous, and more. 345RWHP/354lbsTQ 12.8@108