What do you guys think is the most durable sealent on the market? So far, I've tested Zaino Z-1, Duragloss 105/601 and Col 845. So far, the Z-1 has proven the most durable, by far, on my vehicles. Keep in mind I live in Michigan so I have to deal with winter, salt and lots of car washing. Any other products out there worth trying or should I be trying combinations for max durability?