building a DMR

All AR series will have some wobble, it's te nature of the design. Are you planning on doing the work yourself or sending it away? Could you tolerate plastic externals for the sake of price? We need more info. What are your field limits, What are your priorities etc etc. Btw, make an intro post or Fuzzy will come get you.

In reality, you need to choose a gun, and build the system around that. Because I'm lazy, I'd recommend an ICS M16, but thats just me.

That's the one I'd choose, mainly out of laziness, but if you feel like going the extra mile, a G&P or VFC will have much nicer externals, but internals will require a lot more work.

Probably not an SR-25, probably a variant of the SR series though.

Flat hop is a development of the G-Hop of Ishioka over in Japan. Freind designed and it's only to work with High heavyness ammo and can be a RPITA to install depending on your skill level. It can involve modding the barrel, hop up, and hop up arm as well as the barrel cut. It's also very picky and if your not doing the work yourself, you should avoid as it can be a major tuning problem.

In your position, if you went with the ICS, I'd get the bushings replaced (they're somewhat soft), the gear shimmed and properly lubed, and a Fet installed. This will insure that your gears run smoothly and quietly and you get maximum energy transfer through the MOSFET. As for the Upper, just AoE, Sorbo, and get Maximum Compression. Most of the orginial compression parts can be recycled for the build. I suggest looking into the Holy Grail of DMRs and that should explain a bit more.

It's in the hands of the tech to be honest.

I'd start with looking at SHS parts.

You can get metal CYMA M14s which are actually really nice...