Get yourself a set of extractors, a single 2.25" system with a good quality muffler.
Hunt around for a Redline torquer 2 intake manifold and a 350holley (there will be people on here with a dozen other suggestions, Webers from a Falcon for one. The 350holley is the EASIEST and cheapest carb to use, best bang for buck as well. Anyone who argues that is a muppet).
Upgrade to an electric distributor and make sure the rest of the ignition system is in good order.
Change to a twelve port head, if you don't already have one (Only the red motors don't have them).
Upgrade the cam, which cam will totally depend on what you want to do. When you do the cam, remember you'll need to do the rest of the valve train at the same time (short of valves obviously). Personally I like to use timing gears, but its been a number of years since I played with a 202. So there may well be better products on the market.
Look into roller rockers as well, I'm not sure if they're availible, but if they are its definatly worth looking into.
After you get this far you're looking at rebuilding the motor. Which is essentially the point where you buy a 308.
For the record, its not feasible to stroke a 202.
It is possible to get an intake manifold to suit a 4/71 supercharger, I wouldn't do so with the factory bottom end.
Turbo charging is dificult with a carbied 202, and not worth the effort In my personal opinion (They can make good power, but the constant head aches make it not worth while. Been there done that. We made 317bhp@17psi before we lifted the top off a piston, it lasted 4 months, give or take a week.)
If you're really keen, you could go EFI. DO NOT use the factory setup. There are many generic fuel injection systems on the market. Most all of which are far superior to the 27yr old ancient history of a system that holden used in 1986. The only useful item maybe the EFI intake manifold.