Preamp modifications - who would you use?


I am looking for a company or individual who performs equipment modifications to take a look at a preamp I own and recommend (and implement) parts improvements and or modifications to squeeze out the last bit of sonic performance. I would like to talk with someone who is well regarded not only for the quality of their work but also for their customer service, and who has enough experience and expertise to assess each piece on an individual basis, and not simply apply the same bag of tricks to everything they touch. Based on things I have read, folks that come to mind are Kyle Takenaga at RAM, Bill Thalman at Music Technology, and Chris Johnson at Partsconnexion. I would be interested in other recommendations. Thanks.
mitch2
Vinyl Renaissance

10922 Shawnee Mission Pkwy

Shawnee, KS 66203

913.9620014
I think these guys are great and very fast. My prime choice for upgrades and/or repairs.

Chris Johnson has done some great work but shipping to CA is a pain in the butt and expensive.
John Tucker at Exemplar Audio is very well respected. He is quite busy and may take WAY too long.
Mitch Singerman at Head Fi is another quality choice but again quite busy.
David Gill of Gill Audio Design. He certainly seems to have the approach you are looking for with his own products as well as Art Audio.
Bryon,

Thanks for the review. The room correction and crossover features in some of the better pre-pros has me thinking about using one of them in a 2 channel set-up, but I have the concerns that you mention. I was wondering whether any of the good mods guys handle pre-pros and thank you - and the other respondents here - for covering the subject.

Regards,

Marty
Actually, I also agree with Grant. Didn't know the component that was under discussion - my fault. There are a certain level of components that should be left as they were designed and implemented.