so I got an Adams Arms XLP Gas block (with drive rod spring, and bushing) on the way, and a Midwest Industries Rifle Length Gen II 2 piece FF rail to go with it.

So I'm going to yank the existing gas block of of my S&W M&P15, take off the Delta ring and attach all this stuff and head tot eh range.

so, got those of yall who have messed with Piston systems, what tools do I need, and do you have any tips (particularly for removing the delta ring)

I've worked on M4's before, but this is a new level of fun for me, since I've never really mokeyed around with the slip ring, and I'm like a kid waiting for Santa right now.

To properly remove the delta pack you need a block vice like this one: http://www.midwayusa.com/product/730930/dpms-upper-receiver-action-block-ar-15-delrin?cm_vc=ProductFinding, an armorer's wrench and a torque wrench.

1 - mount your upper in the vice block
2 - use the armorer's wrench and a breaker bar to loosen the barrel nut
3 - remove the delta pack (your original gas block should have already been removed by this point)
4 - If you are going to reuse the barrel nut use snap ring pliers to remove the snap ring from the delta pack and remove the delta ring and spring

You need the torque wrench when you install whatever barrel nut that your rail uses. For the standard nut, torque to 30 lbs, then continue until the next gap in the barrel nut that lines up with the gas tube hole.

The only suggestion I have (other than watching the many youtube installation videos) is to replace the cam in your bolt with the POF roller cam to prevent the gouging in the upper receiver that commonly happens with piston kits. It's not really necessary, but it is smoother.

Thanks for the advice!
It's a M&P PS model, so yep, probably should have changed out the cam 2500 rounds ago. Spent a while wondering what the weird little chip in the upper was. Might do taht for damage control in hopes that it doesn't get worse.

and to answer the next question, I'm yanking the S&W piston and replacing it with AA because S&W discontinued it, and to boot, I can't put a rail on around the existing gas block. Replacing the whole thing is the most economical way to do all the above.

The link I originally put up was for a 308 pattern vice block. I edited it to link to the proper AR15 style vice block/ Sorry for the mistake, and hope you didn't buy the wrong block.