Yo,
As the Title says, I've got me a Little 4runner with what seems to be 4 Inchers built into the rear sidewall/trim. I spoke to an Audio Expert, who said it's good to cut it open and take the little ones out and wire 6x9's. But, I thought that it might be easier to just get Enclosed box speakers and mount them...

An Advice for best replacement parts/ideas on instalation/helping hints?

"I made them wish they had a Toyota"

 

If the setup is still factory, there is a ported box in each quarter. It is just a 4", but it is amped, and puts out a good amount of sound. Rather than hack it all to pieces, just replace them with better quality 4" speakers, and leave the box and amp hooked up.

If you take off the 1-piece quarter trim, you will see what I mean. Dont forget to take off the center upper trim first, there are 2 screws hidden underneath that.