Most people will suggest a timing plate since keys can shear. Granted I ran a degree key for 2 years without a problem but when I rebuilt my engine I swapped over to a ricky stator plate. Most people don't ever adjust em after the first tuning, but its nice for the peace of mind. Besides, its only $35.
Either advancing the timing or raising the compression is a good mod, but you can only go so far. What that limit is depends on your elevation and whether or not you want to run race gas. At sea level, you'd prolly be best not going over 22cc domes and +4 advance. Higher elevations can handle smaller domes. If you don't wanna drop a couple hundy on a head, you can get your stock head shaved for under $50. Just don't go over 30 thousandths or you'll run into squish problems. Only drawback to that is you don't get the additional cooling and you can't change domes. On the otherhand, your engine will look more stock so you get that sleeper effect.