Hi Yomon...You really only need to post once and we'll attempt to answer your question.
Your questions are very broad in nature. It's hard to say what amplifier is going to be needed until the speaker issue is resolved. To resolve the speaker question, in all honesty, you can't design a good box for your drivers if all you know is the impedence (4 ohms) and the cone diameter (10 inches). You must have the electrical and mechanical specs (known as Thiele/Small parameters) of the drivers to design the correct enclosure. It is a highly specialized area and unless you have those specs and a good piece of modelling software, you're only guessing. My opinion; save up and buy a ready-made set of HT speakers unless you've had a lot of hours in the design area. I built my own large system (see picture below) and I can tell you it took hours to get the alignments and other setups correct. The large units you see in the picture are probably the 30th pair of speakers I've ever built and they took about 150 hours start to finish and I haven't even put a nice finish on them yet! The sub-woofer is not shown. Sorry to put water on your coals but that's how I see it. Hope this helps....Lee
