McIntosh tube upgrade - worthwhile?

I am using Gold Lion 12AX7 tubes in the phono section of my Mac C2500 preamp.  The other four tubes are the stock JJ McIntosh branded tubes.  The Gold Lion tubes gave my vinyl a slightly richer sound.  I bought them from Uncle Kevin at Upscale Audio.  They were rated “Kevin’s private stash” and are extremely quiet in the MC phono stage. 

Yes, I put in inexpensive NOS RCA's into my C2700 much better then those JJ's. Even better results with better tubes as the NOS RCA's are not known to be the best NOS tubes out there but better then the JJ's. I also put in some NOS Svetlana 6550 in my MC275 and that was a much bigger difference, better to me. I'm currently looking for better NOS tubes but get those JJ's out of there they are bright, lack bass and sound lifeless. For new production I like the Gold lion tubes.  

It’s strange but why is McIntosh and inclined to tell people stock power cords and stock tubes are not worth upgrading. Most manufacturers sell mediocre tubes and power cords along with their equipment because they know people are going to upgrade it all by themselves.

But McIntosh makes an emphasis to say hey we have designed  amplifiers in a manner that doesn’t make higher quality tubes meaningful. Actually JJ tubes tend to go bad more frequently as I’ve replaced many at this point after just a few months. they Buy them by the batches and they don’t quality control the tubes. Why would they quality control tubes when it doesn’t matter what they put into their devices according to them.

Very strange attitude they have. But I have a few of their amplifiers because they are built like tanks and they’re reliable for the longer term hopefully.