Hey Mate,
Really love the way you have done this and looking to do it to mine now,
Its very hard to source the double din kits for the skyline however i came across this and was wondering if it would work: https://conceptzperformance.com/nissan-jdm-double-din-conversion-kit-black-infiniti-g35-03-04-sedan-coupe-v35-27500-al7kt_p_34671.php
And the other question i had is by any chance do you remember the part number or the name of the Pioneer headunit
Any answers would be greatly appreciated