the speaker size are 5 1/4"
I just bought some Boss speakers... they are amazing... the RD 524s.
If you want you can go NAME and buy some Alpines, or Clarions, or even Rockfords...
thing is, it depends on your budget. Did you change the back ones yet??
The best feeling is beating a Civic Si with an Accent!
http://www.geocities.com/project_gsi/