Lotsapins, good info, I figured the 4" will look good, would be great if they could be mounted recessed in the "tubes" as stock. I was thinking of maybe not use their housing at all, and just use the faceplate and the electronics, somehow. I wonder if I can fit the circuitboard in my excisting frame... I guess I have to order one and take it apart to see if it can be done. Really nice Challenger build your'e doing!