We've experimented with several handling upgrades and found an upper front stressbar and larger front and rear anti-roll bars helpful. Neither of these upgrades will impress you as much as going to a set of Bilstein sport struts on the front and sport shocks on the rear (the "heavy duty" models are valved the same but are slightly shorter).
Neuspeed Sof-Sport springs are a good street handling choice, which really don't ride that rough on decent pavement, will absolutely astonish you with the handling improvement and increase in tire grip you'll experience on the street or at the track. This is perhaps the best VW handling secret we've ever found, and it works for all VW's. Bilsteins and race springs ride very firmly, but the ride is quite tolerable unless your city has lots of rough pavement. I found that many low profile (45 series) tires hurt ride quality more than race springs.
If you aren't quite ready to replace your front struts, you can at least make them feel better than new simply by changing the oil inside. Simply remove the cap, drain the old oil, and pour in some mineral spirits to clean out the crud. I found that Golden Spectro Racing Fork Fluid (designed for motocross cartridge forks) works much better than whatever VW used. This is available in 2 viscosities. I preferred the heavier (125-150) version. After pumping the mineral spirits through the cartridge a few times, empty it out and let it drain completely dry. I recommend you don't pull the shaft out of the inner cartridge, because the seal is difficult to stuff back in place. Fill the strut up about 2 inches short from the top with fresh oil, insert the cartridge and pump the shaft to fill it. Add oil as needed. The strut should end up about 2 inches short of full with the cartridge completely bled and the shaft fully "in". Reinstall the cap, and pump the shaft through it's range to test for uniform damping without restrictions.
While you have your struts off, upgrade the strut bearings to VR6 models, which bolt right on. A number of VW specialists, including your VW dealer and Autotech, sell the whole VR6 strut bearing kit. This largely eliminates the clanking when shifting hard from first to second.
Concerning brakes: The G60 is fairly competent in that respect. I did try some special race pads (carbon/kevlar from Performance Friction) that stopped like a true race car, but they destroyed the rotors in short order, and the dust from the pads and metal from the rotors ate into the wheels so deeply that the wheels had to be stripped and repainted. If you use these pads for the track, wash the wheels after each use. Never use them on the street. Mintex pads (from Autotech) work great on the street. Some serious testing has shown that Ferrodo's new street compounds are even better.
What about fluid? I had good luck with DOT 5.1 brake fluid (various brands: Lucas Girling, Motul, ect...) but avoid DOT 5 like the plague (especially if you have antilock brakes). The absolute best race fluid (available from motorcycle shops) is Motul 300C Racing Brake Fluid, but you'll need to flush the brake system well before installing it and replace it completely once a year. Repeat after me: every year.
Speaking of replacing brake fluid, even the best fluid after several years of use won't resist boiling as well as good old garden variety DOT 3 that's fresh. That's why VW insists on a brake fluid change every two years. Clean out the system and add fresh fluid; you'll be amazed at the reduced fade.
Concerning alighnment, the Corrado responds like every other VW A2 chassis. I was able to run 1.5 degrees of negative camber on the street for improved cornering without undo tire wear as long as toe-in was set at zero. If your car pulls to the right or left, it typically won't be the alighnment (unless something is bent, upsetting the caster) First suspect low tire pressure or a defective tire (which could have been damaged or worn uneavenly by poor alighnment), then look for a bad strut bearing or wheel bearing. Keep the rear wheel bearings snug to minimize peculiar tire wear (cupping).