Musical Concepts modification of B&K pre and amp?

Hello,

I have ave the Pro-MC10 and EX 442, both Sonata Series.  The are no noticeable problems, at least to me, but they must be 30+ years old.  Other than a Yamaha receiver about 15 years ago when I started playing vinyl again, these are the only amps I have experience with.  I don’t have audiophile friends, and I’m not interested in listening to the limited lineup at the only audio store (mostly home theater now) within an hour and a half.  So, I haven’t heard any other high end systems.  I really my B&Ks from Gillian Welch or Lucinda Williams to Talking Heads to Neil Young with Crazy Horse.  But you should hear the Talking Heads.  

My system - Soundsmith SMMC1 cartridge, Mofi Studiodeck on the way (both B&O RX2s have called it a day), Musical Surroundings Nova Phonomena phono preamp, the B&Ks, refurbished Ohm Walsh 4’s, 2 REL T5 subs.

So my questions are:

1) would Musical Concepts modifications address a potential failure just due to age?
2) what would I need to spend on what would be comparable new preamp and amps?  I’d love to try the PS Audio BHK pre and amp, but am certainly not willing to spend that much now or in the near future.

So, I am weighing leaving well enough alone ($0), Upgrading my sound with Musical Concepts mods ($1,000 - $1,500), or New amps of better or comparable sound (?$)

I think the Ohm Walsh speakers like the 200 watts, and the music room is about 15 feet wide and 40 feet deep.

Thanks for your thoughts,

Steve