any tricks to simply replacing the distributor cap and rotor on the 240? am I going to mess up the firing order by just removing the wires 1 at a time and pluging them into the new cap ?

seems like about 1/2 the time, the rotors WILL NOT come off the dist shaft. I grab them with big channel-lock pliers, that works pretty well. Don't be surprised if you crush it or crack it. I have started adding a little Never-seize to the inside of the rotor prior to install.
Be VERY VERY careful if you pry against the top of the dist housing- it is thin aluminum and fragile!
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Rob Bareiss, New London CT ::: '87 244DL/M47- 234K, '82 245T/M46-182K, '89 244DL/AW70- 212K Not too distant past: 86 244DL 215K, 87 244DL 239K, 88 744GLE 233K, 88 244GL 147K, 91 244 183K

Best trick for me is to label each wire with a piece of masking tape. Just number each wire, and you can't screw up!

You will be fine. Just remove the old cap with wires attached and move it aside, remembering keeping it oriented the same as it was on the the distributor. Then put on the new cap the same way the old one was and move the wires to the new one one at a time in their same places. I think the distributor is marked with firing order, but you won'e even need that. I would probably replace the rotor at the same time. The old one might seem to be glued to the distributor, but careful prying with a big screwdriver should pop it off.
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Andy in St. Paul, '91 745 Regina 198K mi, '89 244 142K, '87 245 RIP