Bosch doesnt make platinum 4's for protege 5's (i checked), i have the Autolite platinum pros in mine, they seem to make a little better throttle response, imo its worth the few bucks
Bosch does indeed make Platinum 2's and Platinum +4's for for the Pro5's. The trick is to look under the 2001 Protege's with the same 2.0 litre engine. I beleive the displacement in cc's is 1991cc. I'll post the part number in a bit, once I call my roomie and find out what the number was that I gave him.
Here are the part numbers for the various spark plugs available for the Mazda Protege5. This will be a viable option for the 2.0 litre engine in any 2001 and up Mazda vehicle.
I'm not sure if these part numbers are just for www.mazdapartstore.com or not. But if so, you can find them there, just by searching for the part numbers. After calling them, I found that they didn't have the Bosch number on hand, but I'm still looking.