An AWFUL lot of what you can mine from the web or members here will be legacy Roland styles. Sure, they WILL work in an E80, but they will likely sound nowhere NEAR their best.
If I were you, one of the areas of the OS that I would spend the MOST time learning is the style Makeup Tools. This is where you can alter sounds, effects, dynamics and a lot of other things globally for the style, including selecting the best new E80 tones for the style, the best new drum kits (this is the main thing, for me...) and easily edit the drum kit. Change sounds in the kit, change velocity and volume (VERY important for hitting those vel-switched drum sounds right), change reverb sends, then the icing on the cake... Change the EQ for each drum individually, if it needs it.
It can rapidly (or slowly, depends on how you work!) change a pile of poo into a polished diamond you would be proud to use live...
It is my #1 most used piece of the arranger, and is still one of the primary reasons I stick with Roland. If they make tweaking styles easy, you are more likely to do it..! And that will make for a better comparison sonically between E80 ROM styles, and whatever you pick up out there in styleland, and hence make you HAPPY to use them. And, IMHO, variety of styles is the one thing that keeps you coming back to an arranger year after year after year...
Give the Makeup Tools as much time as you can. It WILL pay off for you...