I'm going to work off of the basis that you have an automatic car. Overall this is a short and rough list of needed part, the 5 speed swap is easy on the 87-91 cars since the mounting is the same between autos and manuals.
For the 5 speed swap: Find a donor car and get:
89-91 v6 5 speed tranny (ideally)
Both shift cables, the shifter assembly
Clutch pedal assembly
Clutch hydraulics (master, slave, reservoir, lines, get as 1 piece)
5 speed flywheel
A clutch/p.p. and t.o.b.
Both axles
chip from the donor car
For 3400 swap (short/rough list):
3400 engine...
Custom made front mount bracket
3100 power steering pump from Beretta or Corsy
94+ V6 Lbody throttle cable & brake booster vacuum hose
Lower radiator hose from 99 Pontiac Montana - use as new upper radiator hose
You will re-use:
Your alternator and mounting bracket
Serpentine Belt Tensioner
Oil Pressure Sensor
This link is quite helpful as well:
http://www.domesticcrew.com/installguide.htm
I recommend getting friendly with it.