i have done both bmw and mazda belts, but our mazda's are 2.3. i think the 2.3 timing belt is WAY more difficult than the M20. especially the water pump. on the 2.3, there is a crossover pipe that connects to the upper rad hose, and this has 2 o rings that you MUST get. to get the water pump out, you gotta loosen all the bolts, then there is this sheet metal plate and the crossover pipe that you kinda wiggle out first. crazy design. the actual motor mount bracket has to come off to get it all out. a water pump on the m20 is right there, on the 2.3 it is like an entirely new job by itself, but i would definitely change it with the belt. however, the mazda belt interval is 105k, not 60, and the engine is not interference. on the m20, we always changed the cam/crank/aux shaft seals, on the mazda, the cam seals are a real bitch to get to, but if you are doing the valve cover gaskets, you might want to get them, too. make sure your valve cover gaskets have the half moons, and the little plugs that go by the cam seals. a head set might be a good idea. generally, the cam and crank seals last a long time. again, this is a 2.3, and the tensioner i think sits different, but when lining up the belt, where it snakes around the crank sprocket, you need something to jam in there to keep it against the sprocket. i found that a wooden clothes pin is perfect, and i now have a couple in my tool box. i also really like the gearwrench serpentine belt tool, it is way better than the kd one, and the 2.3 has 2 automatic tensioners, which are a bit tricky to get off. bleeding the cooling system after the water pump on this last job really kicked my ass, and i ended up buying the airlift vacuum system:
UView 550000 Airlift Cooling System Leak Checker and Airlock Purge Tool Kit
there is also an economy version for less. now this is the ONLY way i change coolant in a car. if you know anyone that has an E38 740, they will tell you what a bitch bleeding the cooling system is. all the good shops use a vacuum system.
u joint sockets are really handy in this job, like these:
Northern Industrial Universal Joint Sockets ó 3/8in. Drive, 7-Pc. SAE Set | 3/8in. Drive Sets| Northern Tool + Equipment
also, ratcheting box end wrenches, and a good assortment of extensions. a magnetic pick up tool is invaluable. i would not do this job without impacts(mine is 600ft/lbs, a wimpy one will not get it done), esp for the crank pulley. oh, and BEFORE you remove the serpentine belts, loosen the nut/bolts on the power steering pump and the water pump pulleys, or you will be sorry. on the power steering pulley, this has 4 holes on the outer rim, and you can use a couple of long 6mm bolts to anchor it if you have to, but the water pump pulley is smooth, and only a really good strap wrench will work if you pull the belt before loosening the bolts. on the 2.3, i think there are 3 different length 6mm bolts holding on the belt cover, and you will go crazy trying to remember which ones go where. you might want to take a piece of cardboard, and draw a pic of the cover, and put the bolts in the corresponding place. also, there is a metal pipe for the vacuum pump that must come off and go on before some other parts can come off/go on. this is one of the few times you will wish you had a 2.5 instead of a 2.3, if you do have a 2.3