Okay I already have most of my componets to complete my build, but trying to decide if I should change some of them out. I have a regular sized dvd drive, hard drive, and a micro atx size board. I am planing to put them in custom plexiglass case. I have a 1'x1'x3'' sized area to put it in.

I want to know if it is better to switch to a laptop sized dvd drive and hard drive to make it all fit better. I doubt that dvd drive will fit inside the case so I was thinking about a ide-usb conversion cable. Do these work well enough?

I did a quick power calculator I found on the forums which said that I will be drawing around 111 watts, so I was looking at 140 watt dual output power supply. Does it have all the connections I need to power my stuff. I need the standard plug for the mother board (I think 32 pin) and it needs the little 4 pin one. PLus i need at least 2 four pin cables.

Since the case is going to be under the passengers seat what will the heat factor be like? I must note that I live in texas where heat can be a issue, but nothing a decent sir conditioner can't fix. I was planing to have two fans, one pulling air from the front and one blowing air out the back to get a flow going. Can I just get two case fans and hook them up to the power supply?

Okay thats alot of stuff to read so to recap:
1. should I switch to slim size hardware?
2. do ide-usb cables work well?
3. which power supply should I go for?
4. heat solutions?