Help for replace my HT speakers
 

Hi, i'm interested in replace the speakers from my HT, sony DAV-DZ315 frist and hereafter replace my receiver.

i'm thinking on build 5 wood boxes with 5 Tang Band 3" or 4" full range speakers or similar, something max 25$ per box.

But here's my questions:

1 The speakers i have thinking is W3-881SI 3" or similar, but it's says that have max 30w, and on specs of my HT says 140w per channel with 3ohms, it's realy loud but i guess that it's not that much since price and size of it, so this is some marketing thing or this have realy 140w per channel?
Sony DAV-DZ170 Speakers only | eBay

*I can lose a little "power" since the room of this HT have 16m² but i want to give quality.


2 What's the best speaker/speakers for this? 1 or 2 full ranges, 1 mid and 1 tweeter, etc. (with max 25$ for speakers per channel).