(1998 i think i have the cheap sound system by lexus no pioneer set-up )

I have a few questions but i guess trying to search i had a bad choice of words and didnt get too much info.

1) I know the Gs3 door speakers are 4" i want to upgrade to most likely 5.1/4" all around, Can i do this with the stock amp?? (Im keeping my stock head unit also)

2)How do i removal the speaker/Panel ect....?

3) How many watts is the stock amp?

4)Can i install a subwoofer box with 2 12" speakers if i install another amp???

5)I need to replace the back speakers & i have been trying to remove the back seat for the last year can someone PLEASE tell me once again how many screws and what motion is need to remove it? Is it push the seat down & out, Lift the top, lift the bottom i dunno


Thanks!!

The main thing at this point is to change my door speakers because one of them blew out.

I saved this lexus-kia:

https://www.clublexus.com/forums/sho...d.php?t=155082

thanks but i was hoping i wouldnt have to pay for the info.

Here's another one from search : replace+speakers

https://www.clublexus.com/forums/sho...acing+speakers