You could build a wood frame around the opening and shim them out... it could be made to look nice and would be cheap. Other than that I don't know.
As far as car audio... hmmm they're designed for a much different application... good in-walls would probably spank them in Home Audio.. Personally I wouldn't consider it.
As far as car audio... hmmm they're designed for a much different application... good in-walls would probably spank them in Home Audio.. Personally I wouldn't consider it.