I'm thinking ladder bars even though my bud Miles has done many before and we did one on my friends truck just something I don't want to deal with (adjusting).
I still want to know any info out there some may have.
Back halve the car and go with ladder bars and coil over setup. Much easier adjustment than a 4 link. The 4 link works best in a full tube chassis all out race car with limited front end travel. If you're not going to back halve it, go with cal tracs. When welding the brackets on the rear end, it would be advisable to have a bar through the housing with the necessary ends, so the welding doesn't bend the housing.
each has its merits. the ladder bars are simpler to install, and stabilize pinion angles, but induce chassis lift, and unless properly sized also bind.
as for the others, it will depend on the design you choose. these are more complex, and require more precision during installation, but a good system is quite well rounded, and far more adjustable than a ladder bar settup. you will have to add either a panhard bar or watts link for axle location. i would use a pair of lower control arms to locate the axle fore and aft, a torque arm for transmitting troque to the chassis, and a watts link or panhard bar for lateral axle location, and coil overs to control axle movement. this settup is the most capable, and wont induce oversteer when cornering.
For mostly street use and some track use I would go with ladder bars. They are easier to set up, require less tunning and less trail and error. 4 links are great but you have to take the time and allow for minute adjustments time and time agin to get the best performance. You also have the potential for binding in st unless you have a floater setup so your diff can roated. You will get better overall perfomance on the track with a 4 link, Its just up to you on what you want really, they both have pros and cons for what you plan on using them for. But its hard to beat coil overs and ladder bars on the street
ladders bars are easier to live with on the street. 4 links will bind up on the street when you go over staggered bumps. Ladder bars will work out pretty well for a street/strip application. Save the 4 links for the strip only.
You can get a good set up from just about anyone. Jegs, Summit, Comp Engineering, Chassie works ect ect. Length side is up to you. Most are offered in various lenghts and you just have to get the length that you are going to be able to mount the easiest, that work with your chassie ( wieght , lenght ect ect) Since you have to basically start from scratch as it is I dont think there is a wrong answer. Just talk with the rep and tell him your specifics and they can hammer out all the rough detials. good luck