EBC HH are good with the standard calipers, strong but still road-oriented. There's more powerful but I think you lose too much control/subtlety... With a K6 your standard hoses should still be OK, unless it's got high miles on, rubber hoses work fine but they wear out. (people replace worn out rubber hoses with braided hoses, or replace good hoses and old fluid with new hoses and new fluid, and they're amazed by the difference
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But if you want to do it at the same time, it will never hurt and they're not expensive. I use HEL but they always seem to be too long, even my custom made single line turned up half a foot longer than it was supposed to. Scooby Drew's set for his Ninja were enormous, so we ended up fitting an old SV set I had lying around which were the wrong size for an SV but perfect for a Ninja, funny old game. They're a great company and they always put things right but they can be a pain sometimes. I still like them and I'd use them again.