Well, I don't drag because any monkey can drive straight, but I can't see how lowering the car would help if you were to drag.
If you are going to get tires/wheels specific to drag racing, look for a smaller and lighter wheel, I'd guess a 13 or 14 incher with some drag slicks for the front. On the rear it doesn't really matter except for weight.
It's surprising that so few people have tried autocrossing when it is so readily available and inexpensive. You can run your factory setup, and any protege in even stock form is a great trophy contender in 95% of the regions across the US. The cost is minimal, you don't have to mod the car at all, and it's a blast. What more can you ask for?!?
As for my future mod plans, once the warranty is up, I plan on putting in a cutom cold air scoop (already have the design), LSD, Camber plates, 15" rims and 225 series tires. Possibly going to stiffer springs and adjustable Tokicos all around. (Koni doesn't make them as Mazda screwed them on the MP3. Koni developed the originals and Mazda sold out to Tokico) Hope to drop the car about 1-1.5 inches and add about 3deg camber up front.
Not sure what else I want to do yet, but a turbo kit is sounding nice, though it would move me into street mod class, and that would open a whole new bag of worms to mess with.
Good luck in whatever you choose.