Hi there Mate,
I've not had my Lexus that long and i've done some research on dimond brite.
The stuffs ment to be very good, protects against weather, bird poop, ultra/sun ect and has a 6 year warranty.
Where do you live? as I spoke to the area manager of the company and he put me in touch with a person direct who will do the car inside & out for £150.00.
Amit.