If you are going to spend the money on LRR tires, be sure to look at other (often overlooked) aspects of rolling drag.
For example, brakes that aren't in very good condition can stick a little bit. And when this effect isn't large, people tend to ignore it, as the engine can easily overpower the small drag. But that drag is real, and it saps FE. Which is why I recently had my independent mechanic do a GOOD QUALITY "brake job" on my car. Unlike the fast chains, he didn't do the quickest/cheapest/easiest brake job. He carefully unstuck everything, adjusted everything properly, and lubed up all the "sliders" (on the front disk brakes) and springs (on the rear drum brakes). And since the front pads (that had been put on by Midas only 2 years before) were now almost shot (both due to the poorer quality of the Midas supplied pads, and the sticking in the sliders), he put on higher quality pads in the front (the rear pads still had about 1/2 of their life left in them). Not only should this brake job help FE, but I suspect this brake job to last a lot longer than Midas's did (both due to the higher quality pads, and also the lower brake sticking resulting in less brake wear)!
NOTE: We would have changed the brake fluid, with fresh (reasonably high quality) brake fluid at that time. However, it didn't make a lot of sense, as we had already flushed the brake fluid (and replaced it with this stuff: http://www.valvoline.com/pages/produ...asp?product=51
) a month or two before (so the brake fluid was nice and fresh already). However, if I hadn't so recently replaced the brake fluid, we would have done that as well (as brake fluid is cheap to replace, and old brake fluid can make the brakes work much worse than they really should)...
And my car is around 15 years old, and supposedly has "sealed bearings" that you can't lube up. And while we haven't yet figured out how to get around that limitation in the front wheels, in the back wheels we were able to drill/tap a small hole in the wheel center, and screw in a standard grease fitting. We then squirted in some high quality (full synthetic Amsoil) grease, into those fittings. It worked so well, that the mechanic said it had been around 20 years since the last time he saw wheels turn that easily!
The two mods (above) made a HUGE difference in my "coasting" distance/ease. In fact, until I started coasting more in 5th gear (instead of neutral) when approaching a light, I actually had to use my brakes MORE, as I just didn't slow down "fast enough" when coasting! And even when I'm driving normally, I suspect this lower "rolling resistance" (due to having wheels that spin more freely) is helping FE.
So congrats on your LRR tires. But if you haven't already done a good job of checking your brakes (to make sure they aren't dragging, even a little), and greasing up your wheel bearings (with the best quality grease you can get your hands on), I would look into those two areas as well. Because better spinning wheels can make a huge difference (my guess would be a much more noticeable difference that LRR tires)...