As always, thanks to everyone for the input

Ok so I went to a local car audio place and confirmed that my front speakers are 6 1/2". My questions are:

1. What is the difference between a 3-way and 4-way speaker?
2. Will my head unit be able to run these 35 RMS speakers fine since it gives out 22W x 4 = 88?
3. The sub I am choosing is the self powered Kenwood KSC-WD250, will this just plug straight into my head unit?

Thanks,

Charles