.223 Wylde Build (Need some opinions and guidance ASAP)

[joeg26er]

San tan had really nice receiver sets. Mega was bought out by ZEV but you should still be able to find mega sets or the ZEV are good to go as well.

I agree with all the other suggestions to go with Sionics NP3 BCG if you want a coated BCG. Nickel Teflon is good stuff.

As far as lower parts kits Sionics, Colt, BCM are good choices. Get a builder set and add the trigger and grip of your choice.

Vltor A5 buffer system would also be worth a look over standard carbine

I have a San Tan build, it's nice but a bit heavy duty. The ambi controls are also nice but a bit bulky and proprietary so hope they don't break. There are some fiddly bits in the upper receiver to "tune" the fit which I did not need to use. Radian has San Tan or the same company do their receivers too as they appear identical.
If I had to do it over again, I'd probably pick up a PWS ambi receiver set with the Lightweight upper.

[JediGuy]

RECEIVERS
I’ve had zero problems using upper and lower receivers from BCM, PSA, and Aero Precision; my current setups are a BCM upper on a PSA SBR lower, an Aero upper on an Aero Enhanced lower, and a PSA upper on BCM lower. All fit and fire fine if uppers and lowers are switched around (of course not creating any unregistered SBR’s). Really, do what you want as long as you get something from a quality manufacturer. I would not recommend PSA, as you already stated your willingness to drop the cash on nicer stuff.
Personally, if I were spending whatever I wanted, I would probably buy a Radian ambidextrous lower and BCM/Sionics upper.

The nicest finishes on my receivers are 1) Aero Enhanced lower and 2) BCM upper, in that order.

BCG
My BCM has been flawless through a single carbine class. I have a Toolcraft nickel boron that works fine, but I would avoid in the future due to concerns with the NiB finish, learned after my purchase. However, my next purchase will be a Sionics NP3 (nickel teflon) BCG; I’ve used some items treated with nickel teflon, and I’m sold on it for moving parts.
If you’re dropping coin on Gisselle materiel, buy the Sionics and you’ll be in top-flight territory.

TRIGGER
Just depends on how much money you want to spend. My Geissele SSA is a delight to shoot. However, so are the single stage BCM PNT (nickel teflon) and PSA Enhanced (nickel boron) triggers. Traditionally, my understanding is that precision shooters have used single stage triggers, but in AR’s, it seems to be the reverse.
If you want to save some money and get what I’ve read is an excellent trigger, do what another poster mentioned and grab the LaRue MBT-2S for $87. For a two stage, there is not a better deal, and my understanding is that the pull is somewhere between a Geissele SSA and SSA-E; I’ll find out soon, as I have one that came in the mail over the weekend.
If you want a single stage, I know the BCM PNT is solid, as should be the ALG ACT and Sionics Enhanced. As a money-saver, my PSA Enhanced has been flawless...and $30; personally, I’m moving away from nickel boron, so I won’t buy another PSA trigger, but again, it has worked absolutely fine for me, including through a carbine class.
Personally, were I to get another single stage, it would be Hiperfire EDT Heavy Gunner for $99.

LOWER PARTS KIT
I see absolutely no reason to buy anything other than a Sionics lower parts kit. They have several to choose from, including ones with/without trigger and grip so you don’t pile up stuff you’ll never use.

TL/DR:
Get whatever lower and upper you want from reputable manufacturers, with a bias towards BCM and Sionics.
Buy a Sionics NP3 BCG.
Save money on a two stage: LaRue MBT-2S. Or get the best two stage: Geissele SSA or SSA-E.
Save money on a single stage: Sionics Enhanced/BCM PNT/ALT ACT. Or get a better single stage: Hiperfire EDT Heavy Gunner.
Select a Sionics LPK that best fits your needs.

In other words, you could order your upper (or even lower), BCG, LPK, and possibly trigger from one spot.

Also, I did the same thing with the BA barrel pinning for my first real “build.” It does simplify things and give you confidence it is done rightly.