Audio Research PH3 Upgrades

Was interested if anyone knows of a company that is doing upgrades for the AR PH3 phono stage. The upgrade to the PH3SE is quite expensive from AR. If so does anyone have any feedback on the improvement? How the upgrade may compare to the PH3SE?
Hello, Great Northern Sound is the company to go to. Steve Huntley owns it and is great to deal with.
The upgrade is definitely worth it as long as your table,arm and cartridge have been set up properly. A proper set up will give you far better sound for the $'s then this upgrade will. I would also advise that you not have your unit modified by someone other than AR. The factory usually knows best and it will ruin most chances for you to resell your gear at a good price. The least expensive way to get into the PH3 SE is to sell your PH3 (they go for $900-$1,000) and purchase a used PH3 SE ( around $1,500) here on Audiogon....that's how I got mine.