Brainwater - while it has been a while since I visited their website I was under the impression that Ref's top mods involved "silver" transformers and tipped the scales at $2100???
As for mods in general after my 333ES was "Kerned" (Level 1 mods and superclock) I found a larger positive difference on redbook vs SACD. Not that SACD was affected in a negaive manner but redbook presentation leaped forward proportionately more.
I also own a Philips although its still sitting at a buddy's place while I ponder on whether or not to get it modded as well as deciding whose mods to buy into.
All I can say is that you have to have faith in your modder of choice and what he feels will be the benefits to tweaking or gutting your Philips. You won't get your money out of the mods so keep your fingers crossed you'll like the outcome...