"I know that everyone says do not buy at HD because of inferior internal parts. But what if the part number is EXACTLY the same (e.g., the Symmons S-3504-H321-V-CYL-B)? HD is selling it for almost $100 less than Symmons' list price. If the part number is exactly the same, shouldn't they truly be the same?" The others have given you good advice. The Symmons Dia that you can get from HD is the exact same one that you'd get from any other retailer. As has been mentioned, just match the model# and you'll be fine. Retail prices are often discounted from MSRPs. So this Dia package would give you everything you need. Done. No more shopping. If you wanted to go with the Symmons valve but with a different shower head, you can indeed mix and match your own. Example, in my own house in one of the showers I have a Symmons Temptrol valve but I combined it with a Grohe Relax Top4 handheld on a vertical bar. If you wanted to do something like that you could buy any of the Symmons sets from this page. Look for a set that has a shower head, a valve and valve trim, and a tub spout. Probably the least expensive one would be the S-96-2 which should be around $100, but for $50 more you can get a prettier trim kit. For $180-$190, Home Depot sell the Symmons Dia with valve, trim, tub spout, and shower head. The $180 version has the diverter on the tub spout. The $190 version has the diverter on the valve. By choosing one of those kits you can then pick any handheld unit out there. Example, the Grohe Top4 head that I used is about $275. If you went basic, the $100 Symmons valve package with a $275 Grohe handheld would be $375 for everything. You could get the "prettier" Symmons valve and trim for $150 plus the $275 Grohe handheld for $425 total. Or the Dia valve and trim for $190 plus the $275 Grohe for $465. Or just the all inclusive Dia package for $415. If you do shop separately for a handheld, make sure the handheld package includes the handheld shower head itself, the shower bar, the wall outlet, and the hose to connect the handheld to the outlet. FWIW, when mixing and matching, "chrome" is "chrome". Be it chromed metal or chrome-coated plastic, they all match well. Good luck!

Just so you know exactly what I have...The two rings that trim out where the grab bars attach to the wall each have circlular section that are a slightly warmer tone, almost satin nickel-ish compared to the rest of the chrome grab bar. It would probably normally bother me a lot, but after a total gut renovation on this old houseI've had to let go of perfection to save my sanity. Especially on things that I might only see for a moment each day when I turn the shower water on and off. Also, at the time I was shopping for grab bars, these deltas were the style, function and best price point for us. I'd buy them again. I might request replacement trim pieces after I get a kitchen counter, but right now they're way down on the renovation's prioritized to-do list.

I can't say if Hansgrohe handshowers are the "best" because I have not tried that many, but we have been very happy with the last two and are installing a third. The Raindance bar has a channel down the middle. There is an "arm" that arcs out to hold the handshower and the arm travels up and down the channel. There is a hinge in the arm that lets it be turned left or right. The handshower rests in what looks like a ball socket at the end of the arm that lets it be tilted forward or backward. It is hard to describe. You should go look at one in a showroom. Hansgrohe makes several wall bars, but the Raindance Unica has the widest range of pivot adjustments.

I don't agree with what Chispa's said. We had a Grohe fixed and a Grohe handheld in the same shower. They were used concurrently nearly every morning for 26 years and neither had stronger flow than the other. If you have the same size supply pipe, the pressure should be the same all else being equal. We had a 1/2" line to the fixed shower and a 3/4" inch line for the handheld and body sprays (no diverter). All could be on at the same time with excellent (and at least equal) pressure. The shower heads on both showers were the same.