The "M" means Mexico. The "Z" means year 200x, the "4" makes it 2004. There are some quality control differences between the MiMs and the MiAs, but if you're on a budget, it's my opinion you really can't go wrong with a MiM. I really feel I got a bargain. I prefer this particular MiM over the latest Standard MiM I test drove at a Guitar Center, and even over the American Standard that sold for $999.99. Keep in mind these are very subjective observations. Overall, I believe this is one of the "best bang for your bux" deals I've gotten in quite awhile.

For anything I may have missed here, you may want to see my post in the Gear forum:http://www.guitartricks.com/forum/showthread.php?t=24973&page=2&pp=10

Some helpful info:

Dating your MiM (has links to MiAs also): http://www.fender.com/support/mexican_instruments.php

A very good article by an Ebayer: http://reviews.ebay.com/Buying-a-Fender-Stratocaster-A-Guide-for-the-Novice_W0QQugidZ10000000001650626?ssPageName=BUYGD:CAT:-1:LISTINGS:5

Strats by Year:http://www.stratcollector.com/scn/base/84.html

If you look at 1984, the second picture of the brown Strat, that's what my Strat looks like.

PS: I should add that the MiM necks are made in Corona, California and shipped to Mexico. The MiMs are made of lighter wood also (I always confuse alder and ash, so I can't say which wood the MiMs are made from.) I was expecting a real lightweight compared to my MiA, but the MiM feels just as hefty. Strats are/were made in Japan also (MiJ/CiJ- think the "C" means "Customized for")- I believe I read somewhere the MiJs are now made for Japanese consumers now only, but not really sure. The MiJs are supposedly superior to the MiMs.