You need to be real careful with that question. Once you send it out, the shop will probably try to convince you to do EVERYTHING............replace exhaust valves, intake valves, guides, seals, prechambers. Drawing the line is difficult due to the "while I'm in there" factor.

If you chose to do the full Monty, you're probably looking at $1200. However, you can save some costs if you force them to reuse the prechambers and the intake valves, PROVIDED, that they are not way out of spec. My intake valves were .0002" below spec. I forced them to use them again.

I haven't done one in several years, so the costs might not be accurate. I'd suggest you call Mike and talk to him about it. However, all discussions are subject to the current condition of the components in your own head.