Forget the Thermaltake armor LCS, it is essentially a normal full size case with a low quality custom loop, where the radiator is built into the case. In reviews it seems to offer the same cooling as mid range air cooling. The radiator it has built in seems okay, so it might be the block that is to blame.
Unless someone has made it for you, you will have o fit the hosing and blocks together, it will essentially be like doing a custom loop from scratch, just more fiddly considering the radiator is fixed to the HDD cage. Even if someone has already made the loop and is reselling it, it is probably well used and is due a clean or replacement hosing to avoid algae and other nasty things. If this was the case, you might as well be heading down the proper watercooling custom route for all the trouble it will cost you.
If good cooling is all you are after, get a cheap case that can accommodate larger, high end air cooling and that will be the cheapest and most effective way to your heat problems. H100i is a decent cooler in terms of performance but i would never buy one second hand privately. There have been a lot of posts on this forum about the Hxxi's pump failing and if that happens, you cant RMA it since it is privately bought.
Go for a new h100i/h80i or get a cheaper refurbished one from OCuk or go for high end air cooling with a case that can take the size of the cooler you chose. For the h100i, the case just needs to be able to mount a 240mm radiator near the CPU. The H100i is 27mm thick, so make sure you can fit it in without it getting in the way of your motherboard heatsinks or RAM.
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