What are the speaker sizes for a KC SE without the fosgate option?

Front = 6x9
Front tweeter = 3"
Rear = 6 1/2

That front tweeter is tight. I had to do some cutting, not too bad, just takes a little time. If you replace your speakers in the rear, save the old speaker and cut out the paper part and save the plastic frame as a mount for your new 6.5's. They fit perfectly. Put a little sound dmaper in there and they sound awesome...

Anyone else have trouble getting an aftermarket 6.5 to fit in the rear door?

Anyone else have trouble getting an aftermarket 6.5 to fit in the rear door?

You need to make you own mounting plate...or do like I did and use the factory speaker and cut the speaker out and use the mounting plate of the factory speaker.

What size subs could i fit under the seats of my King Cab?

What size subs could i fit under the seats of my King Cab?

All depends on your box depth. I and some others here have 12" subs under their seats.

Check this out. Not sure if its what you are after, but its pretty effective.

http://www.clubtitan.org/postt5346.html