I'll thrown in my $0.02 worth: when I buy my RAW's (direct from Martin), I am indeed buying them from a tuner. Martin's guns are custom and I haven't had any reason to believe they are anything but built and optimized as a custom tuned gun. Even better than a tuned gun: you can order whatever options you wish the 'tuner' to include from the start, and have it covered under the 'factory' warranty. Doesn't get any better than that, in my opinion.
My only 'tweak' that I wanted to see on my gun was an adjustable trigger blade to tweak my finger reach and position to the blade. Rowan came through on that one, so I added that to my gun. Yep, I wanted an Anschutz trigger (still the best out there)-but I found a way to tune my own trigger settings close enough to make it crisp enough to forget about wanting an Anschutz trigger-so the RAW unit is indeed very, very good when its all said and done.
I'm all for trying different barrels but, in the end, you'll likely settle in on one that shoots the best and shoot the ammo that performs the best-letting the other options sit beside 'watching from the sidelines'. I did that too-and in the end, Martin's recommendation has proved to be the most accurate option for my gun (speaking of .25 cal). Having said that, new barrels DO come along and sometimes they even improve accuracy an incremental step more-so there's no harm in trying them out (unless your wife finds out how much you spent experimenting....).
Sean