I would never install delta - but that is my bias. I've never met a professional plumber who recommended delta but it's not like I've spoken to every plumber in the world either. What part do you mean is plastic on hansgrohe ? For example, did you know that all the Grohe shower diverter trim plates are actually chrome plated plastic? I highly suggest at least going into a fancy showroom just to touch and feel the items even if you order them on the net. I'm lucky in that I have a local plumbing supply that sells all the stuff at very similar price to the Internet so I get the best of both worlds. Grohe is very reliable and very respected. many plumbers here like the valves. Hansgrohe is a brother company to Grohe - both founded by members of the same family. Hansgrohe is considered generally having the higher end product lines whereas Grohe has a lot of very reliable, home-owner priced sets. To save money I do have one shower that is not Grohe or Hansgrohe - bought the shower set on Overstock.com basically. Wouldn't you know it, I had to repair/replace the shower mixer after a year. It was under warranty but took up 2 hours of my time. The Grohe shower on the other hand - no issues whatsoever. However, I have found several Hansgrohe lines that are similarly priced to Grohe. And some things you can mix and match whereas others you can not. For example, I recently helped a friend spec out several new bathrooms. All Grohe handheld shower valves and bars and handhelds. But for the "elbow" part that connects from the handheld hose to the wall water outlet, I suggested buying the Hansgrohe elbow instead of the Grohe one. The reason is for the same price Hansgrohe gives you an Elbow with a "check valve." The plumbing inspector will definitely be looking for that check valve as soon has he/she sees that handheld and hose. A picture of your open wall would be helpful to understand your dilemma with no room for a valve. Is this for a Tub - or a Tub shower combo - or a Tub, shower, Rainhead and handheld combo, etc., etc... If you choose more items - obviously the plumber has to connect more copper pipes off the shower valve to go to each separate thing you want. if he is limited with space - can you really have all those different items in your shower? Have you considered having the shower diverter valve not in the typical location? The plumber can put the Shower diverter valve on a wall far away and even on a separate wall from where all the heads and handhelds are. this might solve your problem. For example, it's not uncommon now for people to have their shower valve control closer to where they can reach to get the water started and warmed up without getting wet - like on a totally different wall - perpendicular to the actual shower head. For ideas and pictures - go to houzz.com and do a search for "showers" or make it more specific. They have thousands of pictures.

Update - I received my valves and trim and realized that since I had 2 separate valves, I needed 2 separate trims - which I didn't want. SO, they went back and I ordered the kohler INTEGRATED thermostatic valve/volume control. I also received my shower riser. The valve has a female threaded connection and the riser is unthreaded, so how do I connect them? On a related note, the riser is 5/8" outer diameter, which is standard from what I understand but doesn't seem very substantial to me. Since this is going to be exposed and supported only by a knee wall and 2 attachments to a glass wall, should I try to find a heavier/larger diameter riser? Will a pipe of this size even allow for enough water to give me a satisfying shower? Thank you!

First use a flashlight and check the seat carefully. Some are square drive and some are hex drive. If it is square drive, make sure your square drive tool is long enough to reach all the way through the seat. If its only making a partway contact it could be causing the seat to bind. I am assuming your using a square drive socket on a ratchet. If so, insert the square drive fully, then hold the ratchet by the head with the ratchet handle pointing up. Turn the ratchet until you have full firm contact with no slack in the drive, then rap the handle firmly with another tool. (I use a 12" crescent wrench to rap the handle). Generally it only takes about two or three good raps and the seat will free up so you can turn it. DO NOT USE ANY PENETRATING OILS, remember that is potable water flowing through that valve and you do not want to risk getting chemicals into your potable water. Once you have the seat out, take it to a True Value or Ace Hardware store and they will have replacements. When selecting a replacement you will note that they have Brass, Monel Metal & Stainless Steel seats. If your seat has what looks like a chip on the bottom side of the face, that is generally caused by water quality. I would strongly advise you to pay a bit more and get the Stainless Steel seat. Also, after you install the seat, Make sure the stem is turned to the full open position before you screw it back into the faucet. If the stem happened to be in the closed position, as you make the final turns to tighten the stem body into the faucet it would push your new washer into the face of the washer and instantly distort and ruin your new washer.

Sink faucet, shower head, sure they can be reused. The shower head threads on to the arm, easy to R&R. Faucet hot and cold water supplies are connected with threaded unions, simply unthread. Drain tailpiece can be unthreaded from the trap assembly. Faucet itself is usually attached to the countertop by a threaded nut, you can use a wrench or a basin wrench to unthread that. The shower supply valve? You can do it one of two ways. I'm sure there are others, but I'll mention these two. 1) You can cut the supply tubing that is soldered to the shower valve's ports about a foot or so away from the valve. When the new tubing is made up, the old valve with its 12" stub outs can be connected to the new plumbing with couplers. That prevents you from having to de-solder and re-solder the copper at the valve ports. 2) If you can't or don't want to do the above, you can remove the copper that is soldered to the shower valve's ports. I'd first remove the valve cartridge, and o-rings, etc, anything that can be damaged by heat. Heat the joints, break the joints, then clean them up really well with emery paper to get rid of any solder or flux residue. You want shiny metal. Then the valve can be soldered back in. You already made repairs on one valve. If any other valves you're reusing are old, I'd recommend replacing the cartridge and o-rings with new ones like you did with the other. Hope it makes sense!