I envy an 8 second f2l. Granted my 8 second LL won't help much that'll still barely put me under 20 seconds...but still, I'd love to have an 8 second f2l!
at that point you would be working on getting your cross sub 4....
also, fail thread
My cross is sub4, is his not? I generally lump "f2l" with the cross, when I talk about my F2L time. The best F2L time I've had was 12 seconds but I still only got like 25 seconds or something, it was when I was learning my PLLs and my recog was horrible. My average F2L is between 15-19 seconds.
Back on topic though, if you're at an 8 second F2L, first off not only is that really good, second, I'd start turning faster, especially if your look ahead is already there.