Well, don't worry about "where" it is...because if you don't know where it is you don't need to be messing with it ;) Resetting it does not involve touching the computer itself. Just take off the negative and positive (positive first) terminals off of your battery. Get back into your car and pump the brakes to the floor 3-4 times to expend any remaining power via your brake lights. Leave the terminals off for 10-15 minutes. Reconnect negative first then positive and enjoy a smoother running car.
Actually dude, You only need to keep the terminals off for approx. 10 seconds. It says so right in the manual, and on both Dave Black's and Jeff Lucius's websites. Both are invaluable resources for 3kgt and Stealths
Dude never ever remove the positive wire on the battery first it causes a bigger spark and if there is anything flamable around your screwed always remove the negetive first and reconnect the positive first and then the negetive
If you really want to get at the ECU (located behind radio). Remove the carpeted panels on each side of the console, under the dash. There will be 3 small 10mm bolts holding it in, and 3 wire harnesses connected.