I'm not the best person to answer your questions but since no one else has yet and I'm trying to be a nice guy, I'll give it a shot.

[edit]I guess I took so long writing this that I'm not the only one anymore...

Suspension:
1. For a budget suspension that works well, Koni yellows with either Skunk2 or GC sleeves will be good. Both companies offer different spring rates and lengths but if I'm not mistaken, GC has a greater selection. Also, GC has a "kit" or something to use for use with Konis. Others on this board like CivicSiRacer might be able to give you better info on that.

2. I remember seeing SRR LCA's for 5th gens as items that were either new or "coming soon". They're pretty cool and have urethane or some form of stiffer bushing material but they're also kind of pricey. If you can afford them, that'd be cool but otherwise, I'd consider the usual Integra rear LCA's if you're just looking to add a rear swaybar.

2. I'm not really familiar with roll bars for civics but I'm of the general opinion that they're not a good idea for general street use if they can come into contact with an unhelmeted head. If they're totally out of the way of your head or any passengers', like they would be on a convertible, that's cool. Other people can help you with brands or you can probably go to a reputable race car builder and have one custom made.

3. There seem to be a lot of good tie bars both name brand and copycat out there that will do the job. Generally look for the smallest number of hinges if possible. Otherwise, if the bar is adjustable, you can always "preload" it.

4. I guess I should have asked from the beginning what you are going to use the car for. If it's for road course racing or HPDEs, you'll probably want a camber kit that allows you to dial in negative camber as well as positive like the skunk2. If it's a drag car or a mostly street car where you'll need positive camber correction to get closer to or within spec, I've found that both the Ingalls and SPC kits do the job just fine.

5. If you really want to run a low ride height and you want to stay off the bumpstops, check out the extended upper spring perches by Ground Control or look into having your current ones customized. In the front, you can also modify the way the damper fork connects to the shock to gain extra clearance.

Also, swaybars are a nice way to tune your car's handling. Tires and alignment settings are also key.

Braking:
1. Yards or classifieds would be the best place to get a complete GSR setup.

2. If you want to use 16" wheels, you're going to have to research which brake kits will work with which wheels. A lot of the big brake kits out there require the use of a 17" wheel or a 16" wheel that has that lump on the rim (sorry, I don't remember what it's called) further toward the outside. For setups with a racing caliper and 2 piece rotors and whatnot that will fit under a 15" wheel, check out www.fastbrakes.com. As for your suggested setup, you should be fine. Unfortunately, I do not have first hand experience with any of these aftermarket braking setups so others will have to chime in here.

3. For track use and such, it's been repeated many times that what really matters is the size of the front rotors and calipers. There are a good number of people who track their cars with rear drum brakes without problems. There are numerous setup possibilities for you but I think that even the OEM setup with proper pads and good fluid works perfectly fine. Racing calipers like the Wilwoods and such save weight (a good 8lbs per corner in some applications!) and make pad changes a breeze among other things but you need to find out whether or not this is for you.

You'll be fine with a 4 piston setup if that's what you're looking for. What I have heard about the number of pistons is that it helps with brake modulation because the pistons are smaller. I would assume that distribution of force is better too...but I'm no expert.

When it comes to pads, get the ones that will be best (have the proper heat range) for your application. There are a bunch of them out there but the best ones for street use will not be best on a track and vice versa.

I've always been iffy about lines but I now know people running them without problems so they seem fine. Some people seem to really praise them and some people seem to think they didn't make much of a difference. I think the results might vary from car to car.

Wheels:
1. Woooo, the possibilities are endless so I'll stay out of this one.

Exhaust:
1. I think you'll be fine with 2.25 piping. I think you might need to weld an extension to the exhaust manifold when you get the B series in but this probably won't be a problem. Or you could always wait until then to have the exhaust made. I could be wrong in this department though so hopefully someone chimes in with some input.

Good luck though and HTH!