Mazda Repair: MPV Catalytic Converters (2001), obd2 code reader, mazda mpv

Question
I have a 2001 Mazda MPV 2.5 L V6 with 98,000 miles.  Recently the check engine light has come on.  The folks at Firestone say the catalytic converter(s) are out and need to be replaced and they want $3000 to do the work.  I have looked on-line and can get the parts for about $850.  Any issues in doing this myself?  I have above average DIY skills.  The guy at Firestone said I shouldn't do it myself because the computer will need to be reset... It sounds like he is just trying to separate me from my money.

Your Thoughts?

Answer
if you feel you can do the job yourself the great go ahead and do it, chances are that you may have to have the computer reset but you can easily go to canadian tire and buy your own portable OBD2 code reader and reset the computer yourself for about 200 bucks and it's yours when you buy it so if you ever have to reset it you'll have it for the next time most garages charge 80-100 bucks just to do it so it pays for itself in no time if you use it enough