U told about a firewall, that one is no way a write intensive task, so in this use case it would go well any SSD.
If u really think about a write intensive use case, I would go for Samsung 850EVO devices: the 500gb model of the previous 840pro has been tested to write more than 1.9pb before dying and the current 850pro around 7pb (just google for these tests). The 850 series sport the new vertical nand cells which are said to be tougher than previous ones. This said, I expect the 850evo 500gb to write more than 2pb in its life cycle, which is way more than the average PC will write in its whole life. If this is not enough for u, dell features a lineup of "write intensive" (yes, included in the name) SSDs, which sport around double the cells of their official commercial size in order to guarantee a substitution rate of more (right now don't remember how many times) than a complete rewrite every day for 5 years... of course not so cheap like the Samsung evo models. Have phun!
