Welcome to the Hobby Board, you'll find someone here to answer all/any of your questions.
I purchased a PM25 and the starter kit (good heavens it's been a year and a half ago). The vice. I removed the pivot base, stored it out of the way, don't ever expect to use it. I checked the vise itself for square, parallel,etc, and found that it's bottom was high in the middle about .007 or so. I turned it upside down, clamped it down on 1-2-3 blocks and milled the bottom flat. "Twas a lot of hand cranking, but seems to have done the job. I'm happy with the whole thing, I've put X feed and power up and down on the head, just because I could. I felt my shoulder complaining/eroding as I moved the head up or down.
The clamping kit. Some of the T slots aren't as accurate as they might be, I've had to file the T nuts just a bit to make them slide in the slots, but this is really nit picking. The machine is great, i'ts done everything I've asked it to do. Oh Yeah, I ordered the 2 Axis DRO, too.