Cash is king. I do however have nothing to contribute regarding the difference between Wilbers and �hlins setup.

Went for �hlins springs in front, and saved the rear for later.
The limited progressive ability of the standard front fork might encourage selecting progressive front springs. I didn't bother, as i�m rather light and Wilbers progressive front springs (more or less same as Hyperpro) wasn't recommended by Off The Road in Germany.