If you're going to maintain the bike yourself, you must ... MUST... have a torque wrench. There are many places where you're bolting steel into aluminum and it is way too easy to over-tighten. And they ain't all obvious. There are plenty of other places you don't want to under-tighten, what with having only two wheels and all.
If money is a consideration, go with the HF wrench. I agree they're fine when you get a good one, and any is better than none. The problem is manufacturing inconsistency; they're not all good ones, and it's not going to be obvious if yours isn't one of them. (And isn't the whole point of a torque wrench to actually know, within a narrow range, how tight you're tightening the bolt?)
I'd spring for the $80 or so for a Craftsman 5-80 lb-ft wrench when you can. That (just barely) covers the range of every bolt on your K75. Or a better one, if you have the $$$. Until then, HF. I have a Harbor Freight half-inch drive wrench for tires and Jeep axle nuts and such, which exceed the range of my Craftsman, and where "close enough" is good enough.
Also, sign up for the periodic HF coupon email. I think I paid $12 for my half-inch wrench.