I, like many others, hand wrap, not power wrap. I built my rig from scrap lumber, added a thread tensioner bought from Cabelas or JannsNetcraft.com.
I think the only reason to build a kit is if you don't have a drill press or lathe on which to turn cork rings. You can cobble a usable method to turn them on a drill press using threaded rod. Even if you have to use pre-made cork components, you can buy them without resorting to a kit. Kits don't have the right guide sizes, either.
Do a lot of pre-planning to get the guides you want, check out rodbuilding.org for how to do the Fuji Concept guide layout-it really works and is actually simpler than using a whole bunch of guide sizes-you most likely only need 4, like a 25, 16, and 10, then size 5, 5.5, or 6 single foot fly guides for the last 4 or so. This gives you really light guides on the tip which helps rod action relative to using heavier/bigger guides.
Check out split grip-If you do a split grip you need only have a ring or so at each end of the reel seat (actually don't even need that, but I like the looks of it) and a butt grip of about 2 inches.
Make sure you use hypos to measure your epoxy and rod finish-one of the biggest problems I see on forums is finish/epoxy not hardening properly, and that usually means poor measuring technique. Make sure you rough up your plastic parts before glueing with fine sandpaper or other methods (NOT BIG GOUGES-THAT IS WEAKER THAN USING VERY FINE ABRASIVE).
If you partially submerge your epoxy/rod finish containers in hot water for five minutes before you draw material from them, the material will be thinner, have fewer bubbles, and the bubbles you do make will clear better. Make sure not to get even a drop of water into your finish. A great way to use the expoxy/rod finish is to buy it in the little plastic bottle with the pointed caps, and cut off the tip of the cap point at the place that leaves a diameter that is just a little tighter than the tip on the hypo, then you stick the hypo into the open end, tip it upside down, wait for the air to leave, then suck in what you think you will need. No drips/accurate measuring. Keep the resin hypo for resin, and the hardner hypo for hardner, otherwise you will get a reaction and ruin your hypo. Keep separate hypos for each material you use. They are cheap, and oh so handy.
I just had a builder suggest to me to hold the guides on the rod temporarily for tuning location and for tying by using very small cable ties. Haven't tried it yet, but it sounds like it would work great. Tape the handle on, temporarily attach the guides (run line through them right away so if one falls off it won't be lost), put your reel on, and move things around for best balance and fit (check the length from the reel to the butt to make sure it doesn't catch your elbow) and do some test casting. When you get your setup the way you like it, mark it and get to building!
I think going a little on the cheap side is not a bad idea since you will learn with every build, and it might make sense to use the premium stuff on your 3rd or 4th build. I've built for 40 years, have done about 10 in the last 3 years, and I'm still learning. Not only will you get smarter, techniques and parts change with time, also.
Re guides, Fuji Alconites are very good guides, even with braid, and if you use the small fly guides for the ones on the tip, you will have a very light setup without spending a fortune on guides. Use as little finish as possible-that adds weight, too. I like the lite rod finish as it goes on better without forming "footballs" on the windings. Use A size thread instead of heavier B or D. It is a little harder to use, but you'll get used to it.
You can use color preservative if you want to make sure the color of the thread doesn't change, use multi coats, or you can just put rod finish on the thread without using CP and you'll have much different colors. For example, if you don't use CP on garnet, it will look like a sweet cherry color. Many colors that look like they match the rod will almost disappear giving a "stealth" look. Check it out by wetting the thread on a test winding with alcohol to see what you would get.
I like metallic thread for a little bright trim, silver with some colors, gold with others, although there are many metallic colors available.
Regarding spine, most veteran builders say it doesn't make a difference, but they build in their favorite way relative to spine anyway. I put the spine so that it makes the blank feel more stable when flexed in the manner it will be with a fish on. This puts it on one side on regular casting rods, and on the other for spinning and spiral wrap casting rods. Not a big deal.
Don't start building rods unless you are willing to build more than one. You will get hooked! It is a lot of fun and very rewarding. I've built 3 for my son and just finished what may be my best build ever for his son for Christmas.