My Classe CP700 preamp needs service

It can be worth having upgrades installed, not sure if their are classe specialists or not but I would seek others who have had similar work performed. Might check with Benny at Amina. 

I owned a Classe CP-700 very happily for a couple of years; their customer service is first rate. My advice would be to have Classe repair the unit (back to factory spec.) and then contemplate the riskier question of letting some upgrade company muck around with the unit as a separate decision point.  If you do the latter and hope to have the unit effectively upgraded and repaired in the first iteration, you could (stress this word as there is a limited possibility of this) wind up with a failed upgrade and repair that could put the unit in a state where Classe might not want to touch it....

I would only send any of my gear to where it was born.......they have the parts, resources, and techs to repair it properly

Classe is a great company that manufactures great products to be their best at a specific price point. If you are having problems ( and obviously, you are), then I would send it back to Classe (Canada) for repair. I am sure that you will find they are passionate about their equipment, and can give you ideas on upgrades if any are recommended. You can read plenty of horror stories about poor service from many companies that advertise for "upgrades" or "mods." My perception is that many mods do not produce the effect they promise. If they did, you would see less of the modded units for sale used here on Audiogon. Also, once some "passionate" tech upgrades your unit it may make it difficult to have anyone else repair it if anything goes wrong in the future. This is just my two cents.