You'll want a good clutch if your going to make good power with the L28et, If I were you I would get the 225mm flywheel (which you have) or get the 240mm flywheel (which came on the 2+2 stock or you can get one aftermarket) If you run the 225mm flywheel you will need to get a turbo clutch disc and pressure plate. This subject has been covered many times before but if you get the 225mm flywheel you need to have the same throwout collar as the pressure plate for example.
225mm flywheel 225mm clutch/pressure plate 4 speed throwout bearing
240mm flywheel 240mm clutch/pressure plate 2+2 throwout bearing.
I believe the early 5 speed versus the later 5 speed have different throwout bearing lengths basically you just need your flywheel, clutch, pressure plate, and throwout bearing to match and you should be able to use any transmission you want within reason.