One of the big revelations in the new codex allows you to actually take two of the same weapon. Previously in the old one you could only take two of the same weapon by making it a single twin linked copy of the weapon. The cost on the left of the slash is the cost for one copy of the weapon. You can get two weapons by just paying double the points cost. The cost after the slash is for a twin linked copy, which of course lets you fire only once but re-roll to hit if you miss (but still takes 2 "selections" from the chart).
To be honest now that the new codex is out I can see no advantage to taking twin linked over two weapon copies other than it being slightly cheaper, and the times you just want maximum fire power so you take a twin linked weapon and then a second weapon on top of that.
I am fairly certain you can get 2 pods per suit, I honestly haven't put an XV8 together in so long I've forgotten.
Last thing, I highly, HIGHLY, recommend learning how to use magnets if you plan on collecting Tau. XV8's are some of the easiest things in the game to magnetize and with the versatility of load-outs you will really want to. There's tons of way to do this, you can find them on the internet, here's one that looks pretty simple, just scroll down to "Magnetizing optional weapons and equipment" (I just used one big magnet recessed into each arm/shoulder and pushed little metal tacks into the weapons to attach to the magnet. It holds well enough except that sometimes your weapons will "droop" during combat since there's only one point of attachment)
http://themanufactorum.com/kits/tau/crisis/assembly.htm