Modifications to integrated tube amp: experiences?


Hello Knowledgeable Audiophiles,

I am seriously considering having my Onix SP3 modified.
(I don't know why people sell these amps. I love what it does.)
Does anyone have any experience with the modifiers out there (e.g. Parts Connexion, Hot Rod, or others)?
Who would you send your amp to?
I await your replies and thank you.
rhanechak
The best tube dealer I know is Andy at Vintage Tube Services. He offers a money back guarantee and some of the best selection of NOS tubes available. I have bought GE 5751's from him as well as other 5751 and 12AX7 variants.