The Trek 8.3DS was the big I was planning on getting at first.
HAd my eyes on the 8.4 as well, for the upgrade to hydraulic disc brakes over mechs, but the bikes otherwise were good IMO.
But then I went and test rode at three different LBS, a number of bikes in the same price bracket and feature set.
I ended up going another route, but still got the same stuff that the 8.4DS has. The reason I got a different bike was feel. I test rode a bunch of bikes, and one stood out above the rest as "feeling" noticeaby better. That bike is the Cannondale Quick CX3. (I mean to say, it felt better for ME. I felt more comfortable on it. Not that its a "better bike".. In fact, if you want to compare it to the 8.4ds, the 8.4 has some better components)
The reason I wanted to respond is twofold.
A-go ride as many bikes as possible. Seriously, go to the LBS, talk to them, and ride every bike you would consider owning. If its a good shop, they'll encourage it, and you'll thank yourself.
B- Your weight is fine. Im a smidge taller than you, and a bunch heavier(hence the bike riding
), and Ive been fine. I did research weight limits and stuff, and there is some different and conflicting info out there... but if you wanna base it on weight limits alone... most hybrids either dont have a limit, or are 300lb. Even a lot of carbon road bikes, I was able to find "weight limits" of like 275-300lb suggested.
A gentleman at one of my LBS's said to me when talking about weight limits and such, especially when talking about aluminum bikes which made good sense at the time.. IF you can get on the bike and ride it normally, you're not too heavy for it. Just make sure your tires are properly inflated before each ride, always. After that I pretty much stopped worrying about weight limits and all that jazz.