As for parodius 3, it has an sa-1 chip which is for better graphics or something, but it also has a better lockout chip in it. So to play it on a pal snes, I assume you have to have the cart see an ntsc lockout chip, AND have your pal snes see a pal cart, or disable the lockout chip on your snes. But either way the cart has to see an ntsc lockout chip (american/japanese game.) But even if you did get it working I don't think the game would run correctly, being the sa-1 chip works fine at 60hz, it may mess up at 50hz. (or vice versa depending if it's a pal or ntsc cart.)
People say sa-1 carts (like parodius 3, mario RPG, power rangers zeo battle) don't work on super nintendos that have their lockout chip disabled. I disabled my lockout chip, and those games work perfectly (beat them all without a single problem.)
I have kirby's fun pak, which is a pal sa-1 game, and it doesn't run on my snes (though every pal non sa-1 games can.) I'll try to make a pass through adaptor so kirby's fun pack will see a pal lockout chip and play.
p.s. that power rangers game sucks ass