Guys, dont forget to use the search at the bottom of the page and also to check over at
http://www.gnttype.org. There is great info already available and waiting to help you (i.e. ECM conversion).
Yes, the '87 ECM plugs right in, but you will need to add a MAT sensor (easy). Any '87 chip, burned for your injectors of course, will work. Some say that a chip burned for a '84 car w/ '87ECM works better. Joe Lubrandt of PTE (219-996-7834) would probably be considered the man as far as this. I have '87chips (burned for '87 cars) that work just fine. I also have a JL chip.
'87ECM part#1227148 can be found in junkyards: $10(?), the JL chip is $50. Chip prices vary. Main reasons for changing over is more available scantool data (Turbolink doesnt supply as much data for '84 as it does '87) and more available scantools (SM), and greater chip availibility (plenty to choose from; everyone makes '87 chips, so take your choice).
START HERE:
http://www.gnttype.org/techarea/ecmsensors/8487ecm.html
Oh yeah, the SM is small. About the size of a deck of cards. Good product. Doesnt replace what you can do with a laptop w/Tlink or Directscan for serious tuning, but it serves its purpose with its size as its a heck of a lot easier to have it sitting on your dash rather than lugging around a laptop. Laptop based scantool would be first choice at the track though, IMO.