I have a 92 Mazda B2200 extended cab pickup with a manual transmission. It has a modified flatbed, but the exhaust pipe has been cut off at the back of the cab. The EGR light is also on. Recenltly I gave the vehicle a tune up for my first time (spark plugs, cap and rotor, filters and whatnot) The mileage is around 160k. Lately it feels like the clutch is slipping out and the car will stutter at accelerating. I assume this is either the clutch or transmission. If this is the case, how difficult is replacing either the clutch or tranny? I've got patience, maybe not a week of staring at metric bolts though...

Probably one of the easier transmissions to remove and replace given that it isn't a 4x4. Disconnect your shifter mechanism, clutch linkage(hydraulic I suspect), driveshaft, any electrical connections, and then bellhousing bolts.

I would expect that to take 4-5 hours at home on the ground with a good selection of tools and a moderate skill level. 14 and 17 mm wrenches and sockets will be your friends.

Good luck!