Honestly, it sounds like you did well. 2.6kg isn't really that bad for a well-spec'd machine -- if you compare it to ultra-book-class devices with smaller screens (and therefore smaller footprint), then sure, but you're getting half-the machine. To get a comparable machine in a more svelte package, you'd pay twice as much.

My Lenovo w530 comes in at around 2.81kg with the extended battery, and I often carry it with an additional sheet-style battery on the bottom that plugs into the docking port. It probably presses 3.25Kg then, but its hard to beat 4-5 hours of runtime under heavy load (gaming), or 10 hours under normal workload (browsing, coding), in a machine of its class.