When I had the Gtechniq full treatment they applied "Leather Guard" which included a 7 year warranty not only for the exterior protection, but the leather seats for staining or cracking.
I wore jeans twice (one time was for 200 miles) and I had die transfer to my cuoio leather. After the treatment, I wore jeans 3-4 times again and checked the seats ... seems to be working ... nothing there, (or it wiped off on my non jean pants .
I was concerned with this open grain leather whether it would come out so I decided to add that to my interior protection.
tjsbeer - I'm not sure if you plan on doing any sealing or coating of the car exterior (like Optiguard / Opticoat Pro or etc ...)? If you are, they probably will do the interior as part of the package, otherwise I would have done it myself since it is real easy.
I'm 90 miles away from the Optiguard folks (in Philly area) so I choose the GTechniq interior and exterior complete protection package since they have a certified detailer in Hershey PA.
Either way you can't go wrong adding a protective layer to those seats. I'd be hard pressed to tell there was anything applied to the seats ... but it certainly helps protect from dye transfer and spills.
I've not tried CQuartz, but heard some positives about the end result.
I've used Zaino Z2/Z5 combination for 7 years with excellent results on my Black Escalade and Thundergray Deville. I put 6 layers on my Escalade in first year to get the water wet look. It held up fine. I typically used 2 coats every season, but as of late 2 coats every 6-months.
I wanted to try something different for the Ghibli, so I went with the stronger Gtechniq protection with professional application, but will still top dress every year with their product. Initial results I'm very pleased ... time will tell.
I just switched the Escalade to "Black Light" and "Black" top coat ... it definitely outshines the Zaino on a side by side test panel due to thickness of coating (I suspect) ... but time will tell on durability since the final top coat is wax based. Not worried since I will top dress at least every six months to keep swirls hidden.
I got excellent results on my wife's Zircon (silver blue) Jaguar with a Chemical guys Jet Seal product. They provided as complimentary with the Black Light kit.
I just put one coat of Zaino Z2 on my Deville today and it made the finish shine like brand new again. So it must be working well.
There are lots of good products out there and it all depends on how often you want to re-protect the car or add a coating that is harder and more rugged than your current clear coat for everyday 4 season use.