Hey Paul - Actually - contrary to popular belief, that car can be made into a decent contender at a street tuned level and can grow to be quite capable on the track. Forget the nay-sayers - as this is a great, often overlooked platform. I don't know what your plans are but I've studied that car for a long time and might have some decent leads as far as resources.
First off, what helps greatly in your search is knowing the chassis code for your vehicle: AE92
(parts you will find under this chassis code will bolt up to your car with little to no modification. Even more will if you swap over to the full range of AE92 GTS components: suspension and brake components, gas tank, and a proper 4A-GE w/ manual transmission, etc..)
From there, you'll find that your door to parts and tuning opens up considerably. (Not as wide as a civic per se, but a lot wider than no parts at all ^_^ )
For starters, there is a decent following on Club4AG.com
you should take a look at their AE92 Light Tuning Guide
http://www.club4ag.com/faq_and_tech_pages/ae92_light_tuning_guide.htm (copy and paste into browser)
Then head on over to Toyota Nation for some ideas in their forum section for 6th Generation Corolla. (beware, a lot of these cars do feature non-functional / aesthetic parts and stuff that just plain doesn't make sense. There are a few people on there though who are more knowledgeable and actually know what they are doing. They will be glad to point you in the right direction.)
Finally, please please check out AE92GTS.com There is a wealth of documented info there on a lot of things I think might help you.
And lastly, some "IMHO" tips from me ^_^
The AE92 GTS 4A-GE motor is often sought after in all those crazy builds you hear about (as a cheaper alternative to the 20v 4AG). While it's a good place to look, there are other options as well. There have been sucessful 4A-FTE conversions for a quicker route to power. You could also source a 4A-GZE motor from the supercharged AW11 MR-2 (1st generation) Which also came in the Supercharged AE92 Levin.
These motors are not hard at all to swap over as long as you have the necessary components. They all exist in the car stock in different markets. To make things easier, get the transmission with the engine. It's enough work swapping an engine, you don't want to go under there another time to swap out the transmission for a manual on a FF vehicle. It's just a pain.
Then of course, there is the 3S-GE / 3S-GTE series found in IS300 (altezzas) and 2nd gen MR-2s (amongst other vehicles - actually, you'd want to source one from a Celica All Trac / GT-Four). These take a bit more fabrication but can be extremely potent.
Personally, I'd go with a naturally aspirated 4A-GE setup but that's just me, I prefer to retain the balance of the car.
I'd like you to know what options are available though!
Coilovers are pretty harsh on the street and unless you are going out for major track time or the local auto x multiple times a month it's really overkill and can actually hurt.
Brakes are not too hard to find....
Decent aero mods are hard to come by unless you want your car to look like crap. Especially for the SR-5 but on the cheap, you can always swap over the pieces from the GT-S which are aggressive enough for most cases. There is also the amazing look of the AE92 Levin front end which has been switched over with awesome results.
You can also switch transmissions to a Celica 6 speed unit if you're going for a decent power making turbo swap or a 20v 4AG (just throwing more options out at you). The gear ratios don't match up too well otherwise.
Start with the Light Tuning guide and then AE92GTS.com
you'll be happy, I promise! Sorry this was so long!
