If he's talking upgraded power supply, it can be worth it. Some equipment is more sensitive to this than others...partly depending on what PSU is being used in the first place.
Can you trial it before buying? I would say good PSU is oftentimes a big improvement in bass, control and a 'stronger, more complete' signal coming thru.
ultimately, first question is do you trust the dealer/manufacturer? Some are reasonably honest and will be right when they say an upgrade is worth it...and some will also try to sell you the next-next thing to make a buck.
Can you trial it before buying? I would say good PSU is oftentimes a big improvement in bass, control and a 'stronger, more complete' signal coming thru.
ultimately, first question is do you trust the dealer/manufacturer? Some are reasonably honest and will be right when they say an upgrade is worth it...and some will also try to sell you the next-next thing to make a buck.