Here is a little food for thought from a post I made in this very old thread...
http://www.mr2oc.com/showthread.php?t=267392&highlight=air+bag
This post is a little more updated now though.
The pre-1997 vehicles have the "old" high pressure air bag systems, ALL 1997+ vehicles are required to have the newer "low pressure" systems (regardless of manufacturer date if it is considered a '97 it has to have the low pressure system). Reason... There are typically MORE low speed impacts (collisions) than high speed impacts where the air bags shine. The old "high pressure" systems have been known to cause 1st-2nd degree burns to face & arms (from packing powder) & the occasional broken nose/jaw or wrist in low speed impacts where a person just wearing a seat belt would NOT be injured. Now, I have still NOT been able to find these old DOT reports on the web though, but I have not been looking any more either.
But, as a Firefighter/Paramedic for the last 20 years I can tell you I have personally witnessed this. I was an "Advanced Extrication Specialist" on Special Operations for the Memphis Fire Dept for 8+ years & would regularly get training & updates on air bag equipped vehicles, I know this to be the case as well simply from experience (thus the change to the low pressure systems). FWIW The low pressure air bag systems may cause some irritation from the packing powder but generally DO NOT cause much of a burn & I have not seen any broken bones from them being deployed. This still holds true & I am now Battalion Chief of EMS & frequent many Motor Vehicle Collisions while on duty & still get the vehicle updates as we have air curtain systems & eletrical cars to deal with now.
FWIW, our mark2 MR2's have the old High Pressure systems, not to mention 24-19 year old air bag components on our MR2's here in the USA. DOT recommends (as do most manufacturers) that air bag systems be "serviced" at least every 10 years. But who has had their sensors checked & calibrated?? Not many I'm sure. This still holds true even for the newer systems.
So, with the older air bag systems, we tend to see impacts that would normally NOT inflate the air bag system actually inflating the air bag & higher speed impacts where you would expect the bag to deploy it did NOT. But, generally the air bags on these old unserviced systems DO INDEED deploy.
It really comes down to your feelings on the situation. I personally have a Sparco 383 steering wheel on my MR2 now. Why, I like the wheel better than the OEM one & I do not trust the old air bag system to function "properly". I feel just as safe in my MR2 as I do in my 1990 Toyota 4x4 that did NOT come with an air bag. Not to mention that the mark1 MR2's did not come with an air bag too. But, I ALWAYS wear my seat belt.
Also, the removal of the air bag ECU & sensors & associated parts & wiring can be considered a weight savings modification, to those that wish to do that (I like did).
FWIW I do plan on putting in an Autopower (or similar) roll bar (with race & harness bars) & putting in a harness for added protection. This is still in the plans too.
Personally I say have the system checked & calibrated if you want to "be sure" your air bag will deploy "correctly". But, again this is personal preference & what you (or anyone else) are most comfortable with.
I was comfortable in putting on that Momo that I used to have & I really LIKE my Sparco 383 (it is quite comfortable & very grippy).
Hope this helps some!
Daniel :thumbup