I'd go with a 1 farad cap... a 20-24 volt cap is a better cap, capable of more voltage... thats not its operating voltage, just its rating.

The ESR is the resistance of the cap... less resistance, the more efficent the cap is. Most caps on the market vary so little, its nothing really important.

The temperature is just its maximum operating temp..

I suggest the 1 farad cap, so if you ever add another amp, or get a different one pushing more power, you'll already have a cap that is most likely to be big enough... plus the extra holding capacity dosent hurt.