try 1z leather treatment for your seats. You buy it at
www.openroadmotoring.com leaves the leather looking new and not greasy or shiny.
As someone stated already FK1 makes a few great products for regular detailing like 425 as an LSP (last step product) and 1000P high temp wax verrrry durable.
I think the most important thing with a dark colored car is to use the highest quality towels you can afford and wash them after each use. Try
poorboysworld.com for waffle weave towels.
p.s.
And try quick washing with
Optimum No Rinse, easier on black paint. Too much soap washing will swirl your paint.