Hi - no kit, have to piece it all together yourself. There is a three way diverter, volume control, theramostatic valve, tub spout, fixed shower head with plate, handheld shower, shower hose and mounting bracket for handheld. I'm not sure but I think the hose is 5 ft long and yes - they come in different lenghts - at least for grohe. If I can find it - I think I may have the invoice. I will look tonight.

Height of the rainshower head? I'd bring it down no lower than about 12" above the height of the tallest user. It can be a bit lower, but try to stay at least 8" above the top of the tallest user's head. Depending on the style of head you're using, 18" to 24" extension will work fine. Most true rainshower heads will not perform well unless they are installed parallel to the floor. So installing them on an angle, as they might be when coming out of a wall? You'll get some "rain" and some "dribble". There are hybrid rainshower heads that are designed to replace a standard head coming out of a wall, but they're not true rainshower heads. They usually have fewer holes to give a more forceful spray. They are "in between" heads. I've not heard of cleaning problems with metal hoses. I suppose hard water could bring that into play. I do recommend getting a hose long enough so that you can use the head to wash down all surfaces in the shower. You can also get additional head hanging brackets, they're only a few dollars each, so you can mount a bracket to hold the head at knee height for shaving legs, etc. Metal versus plastic? Some metal heads are cheesey, some plastic heads are fabulous. I've showered in all types of settings, from razor sprays that are painful to the gentlest of rainshowers. From one shower head to full-blown 24 head spa setups that make you feel like you're in a car wash. When I built my own shower, there were no limitations. My wife had carte blanche, we had no budget. All we did was we put in two heads on two valves. A 12" overhead rainshower, it was about $100 for the head. On the wall I installed a Grohe Top4 Relaxa head on a vertical wall bracket. I'm 6'4", my wife is 5'1". The head is easy to slide up and down as required. It can also be taken off the clip to be used as a hand held. I installed another bracket lower on the wall for my wife to use when shaving her legs. She can sit on a teak bench and clip the Top4 head into that bracket while she does that. I have two separate on/off supply valves, one for the overhad and one for the handheld. They can be run independently or simultaneously. They are simple valves, Temptrol. It's an excellent valve that will never cause problems. $100 for the rainhead, I think it was around $175-$200 for the entire Grohe setup, the Top4 head, the bar, the extra long hose, etc, about $200 for the two Temptrol valves. $500 for the whole shebang. No regrets. In a tub/shower combo, a rainshower head could be brought to the ceiling. There are plumbing kits that have chromed or other finish tubing that can be surface mounted on the wall to bring the water to an overhead rainhead. But mounting a rainshower head on a typical angled arm coming out of the wall? You might not get good water flow out of that. I have installed in-the-wall plumbing so that a rainshower head could come out of the ceiling in a standard tub/shower surround. The setups have had the standard wall tub filler and wall shower valve setup, I've usually installed a diverter valve so the water could come out of the wall shower head or the overhead rainshower head. Nothing ghastly about that at all. I would not have just a rainshower head as your only head. As other have mentioned, it's a very gentle flow of water, and does not do a good job of penetrating hair to rinse out shampoo. Mongo

Although, we are re-doing a bathtub/shower, and I am replacing it with showerhead, handshower and tub spout, and had to get all the pieces separately (didn't care for the Symmons styles). We are going to use a delta pressure balanced valve (but it has separate handles on one valve, one for water volume and one for temperature), and then a diverter (to go to either tub, shower, or handheld). The rest of the parts are going to be Grohe, but they are all from different style lines (yeah, it sounds like Frankenstein but I don't think it will look that bad).

Manufacturers describe things differently at times, but look for a "4-port diverter valve". One port will be water in, the other three ports will outflow to the tub spout, the fixed, head, and the handheld. Some valves are all in one. They have the water volume ON/OFF, temp selector, and diverter all in one valve. Some manufacturers market them individually. You'll buy a supply valve that will give you ON/OFF and temperature selection, and the outflow from that supply valve will feed the IN port on the previously mentioned 4-port diverter. Do understand that when you shop, you'll be shopping for valve bodies AND valve trim kits. The valve body is a cast piece of brass that gets buried in the wall. The trim kit is the pretty (chrome, nickel, ORB, etc) piece that covers the hole in the wall and hides the valve body. In general, you buy them separately, but you need to make sure that the trim kit is compatible with the valve body. So, for the most part, you can either get: 1) the all-in-one valve body and then get a trim kit for that all-in-one valve OR 2) you can get the water supply (on/off/temp) valve body and a trim kit for that valve, and a diverter valve body and a trim kit for the diverter valve. Since you have a tub spout that you like, you'll probably want to get the shower valve trim kit(s) in from the same design group as the spout. Find that rim kit, then websites will usually contain links to find the valve body that fits the trim kit(s) you are looking at. Good luck!