If your going to dump it, I'd recommend getting springs that make your car 2-2.5" lower. I've got my Fairmont lowered 1.5" and although it looks heaps better, I wish it was lowered just a little bit more.. Also when it's getting lowered, make sure the rear doesn't sag. I have this with my EA (sags just a little, but you can notice it, I have King Springs) and it's got something to do with the rear springs being dual rate springs.. (correct me if i'm wrong)
CD Player--- Your not going to get anything for $200 unless you buy it second hand. I'd budget between $250-350 for the most basic of CD tuners.. Just make sure you get a H/U with outputs incase you want to get an amplifier later on (most come with at least one set)
Exhaust--- If you do upgrade your exhaust (good idea, especially on an EA) I'd suggest you save up and get extractors, larger cat and exhaust at the same time. Getting just a Cat Back exhaust won't upgrade the performance of your car one bit, because an Exhaust is only as big as it's smallest part. I'd recommend going a 2.5" Pacemaker exhaust. Don't buy a "hi-flow" cat no matter what anything the exhaust guy says, they are rubbish and don't allow any extra flow whatsoever. Just get a cat that matches the size of the rest of your exhaust. All in all, i'd say $250 for the exhaust, $250 for the cat (correct me if i'm wrong), and $450-500 for the extractors..
Mags--- Ok, now mags would have to be THE most overpriced item you can buy for your car IMO. If you want to go for a nice, yet somewhat common look look for a set of 15" EA/EB GHIA mags. Polished they look very shmik, especally on a lowered car. I also hate chrome mags, but polished mags look very nice. You could buy a set of these second hand for around $300-450.
You could then consider purchasing a set of EL XR Tickford Mags.. They are also quite common, but not seen all that much on EA's, and suit the car perfectly. I've got them on my car and they look very nice. You can buy a set second hand for around $500-600, or you can also buy brand new replicas ($750) or originals ($1100) from any major tyre/wheels retail outlet.
Also, what kind of engine did you get. Was it the 139kw Multi Point engine, or the 120kw CFI engine? They way to tell is if you have a tennis raquet style air filter on the right of the rocker cover.. If you do, then unfortunately you've got the slower CFI..
Hope this info helps you!