3.5 hrs to change spark plugs!

i took my car to the canadian tires shop last week, it had started to vibrate suddenly earlier in the day. Although the checkup did not take more than few minutes, the shop charged a 1 hr labor to hock the car to the computer thing to know what is wrong. they said one of the plugs backfired and the car need new spark plugs, in addition they recommended changing the wires and some valve ..etc. the bill is close to $1000!!
they are changing 3.5 hrs of labour for the spark plugs change! they say the engine is mounted in a way that 3 of the plugs are hidden behind the engine and it will be impossible to change without removing things in the way. it's always suspecious to hear this kind of crap coming out of a mechanic shop. i had no other options, it was near the end of the day, so i asked them to change oil and rotate tires and i schedule the tune up for the coming saturday (last saturday). I returned back on saturday morning, cancelled the appointment, bought a set of tools and sockets, spark plugs and headed back home. waitted for the car to cool and then changed the plugs in my drive way in about 2 hrs.
if you search and browse online, you would know that changing spark plugs for toyota sienna is one kind of job that no one wants to deal with, it's a major pain and time consuming job. next time it's going to take me less than an hour to do the job, that is for sure. And finally to the shop who quoted me 3.5 hrs to do it, thank you, your high qoute forced me to buy the tool set i always wanted and need to do all my car repairs going forward. the tool set was on sale too which is another bonus :)