Preparing to replace Optispark, have some questions.

Hello all.
Skip to second paragraph to skip my rambling.
      Back in early February I bought a '96 Buick Roadmaster Estate. 171k miles, ran good and is little rusty but nothing unmanageable. I've really fallen in love with the car even though it's either been broken down or in a state of disrepair that renders it untrustworthy for daily use, which it is right now. About a month ago I had to replace the fuel pump after it burnt itself out and melted the wiring harness. Hacked jobbed a hole in the floor and it started right up after that. Couple days later started acting up again. Running very rough, and very slow throttle response. Got tested for two engine codes, P0141 and P0107, which are for an 02 sensor and a MAP sensor. Replaced MAP sensor and fuel filter. Problem made worse.  Had MAP sensor defected out, and no change. Took it to trusted mechanic and they determined it needed full tune up including Optispark unit, just what I had feared. Since then I've tried taking it out a couple different times, and had different results. First time it wouldn't start at all, tried for over a day and nothing worked (determined it had fuel and spark but not firing for whatever reason). Next day disconnected and reconnected battery as a suggestion by neighbor and it fired right up. Idled fine and overall ran smoother on the road, but once hiccuped and lost all power for 5-10 seconds. Real odd. Had codes ran again and this time only brought up P0300, which is multiple misfires, but no definitive answer to a cause.  
    So, I've come to the point where I must accept the truth and bite the bullet on this job. I plan on replacing the Optispark myself. I've done my research and decided to get a AC Delco reman unit from Summit (Can't post link but part # is 19212300). I also yesterday purchased new spark plugs, wires, water pump, accessory belts, and front engine oil seals. I believe that should all I need however, when reading the review for this Optispark unit, I found out the wiring harnesses are different on the newer units and that they either need to be spliced or you need an adapter. However I haven't been able to get a solid answer on exactly what adaptor you need for this job. An adaptor (ACDelco 15305942) is listed under the "required parts" tab on the the AC Delco unit's page. Is this literally all I need? I only ask because there are multiple other different adapters listed on the "suggested parts" tab and I'm not quite sure if one or all of those are required to do the job. I'd also appreciate any suggestions on how to make the actual job go smoother or tell me if I'm forgetting any other parts I should replace when I have it torn down.

Thanks,
Ben

personally i don't think our optispark is the problem,. if the car runs good at any time the distributor is fine,.distributors

check your coil wire,.
check the grounds at the cylinder head by the ign module,.

make sure your fuel pump wiring is good,.

Up until that time the car ran rough idling and through the driving range. Haven't tried to replicate it since. Regardless I'll check those and come back with results tomorrow. The issues didn't start until a few days after I replaced the fuel pump so I guess it's possible the wiring is faulty.

I had similar issues, and to +1 what Nick said; cleaning and replacing the ground connection on the block by the coil solved just about everything.

Unless the Opti is throwing specific codes, like missing high/low res signals, that sort of thing- it's probably ok electrically. There are some physical things you may want to check though, like the vent lines and make sure they're working and that there aren't any vacuum leaks at the distributor cap or the bearing. If that stuff isn't working you could get excessive moisture and possible corrosion in there that could affect the cap and rotor but probably not the optical sensor assembly.

I,m not sure where you live ,..but another thing to look at, is your temp sensor in the water pump,. check the pigtail isn't green corroded etc,. the sensor feeds the ecm temp info.