Hey byrd,
Not exactly your same question, but I recall someone in the past asking Taylor to spec in the 510s at order time ...and he found out it was around 2x what it would cost to DIY. Not saying that is at all unfair, mind you ...just saying that you'd definitely be
paying for them to do it, if they'd do it at all in your case (of being in the shop and having to R&R your old tuners). Just an option for you to consider is the DIY route which is a pretty easy task, and you also can look around for exactly which finish you prefer (as there are 4 or 5 different finishes on these 510s, IIRC). OTOH, if you choose Taylor to do the work, I'd personally recommend the "antique gold" fin (which is a satin) over the polished gold machines: looks more "classy" than "blingy" IMHO. As to whether it is "worth" the cost, well that's a valuation Q which is up to you. But since you asked, I find zero fault with Taylor machines, yet I find the 510s worth every penny.

Edward