Rothstein internal preamps?

[derrenleepoole]

Have been doing some research into cost effective upgrades to an SX jazz bass, and I've stumbled across a company called [url="http://www.guitar-mod.com/"]Rothstein[/url] Guitars who make pre-assembled tone units for J & P basses etc. The price of them is very good, and I was wondering if anyone here had used one? I did do a search but only a handful of hits came up. A pre-assembled preamp for a jazz bass with 5 position rotary pickup selection, 500k pots and a choice of capacitors is coming in at $120 approx! Any thoughts?