I've always been notorious for playing online a helluva lot more than offline, infact, I'm of the view that for active competition - if you wanna improve, just go online. Yes, there is lag, frame drops and all sorts of bugs that hinder pilots - but I take that as a given, and try my best to adjust accordingly.

Though offline makes for a much more smoother gaming experience, I find that I cannot sit there and play for more than two races before I go online for like 3 or 4... maybe 5 hours to race. I guess TT and SL would help me to improve alot more but I cant be bothered really lol

I've already optimized my HDTV settings to minimize lag (Game mode), and am using an expensive HDMI cable for connection - I found this helped slightly, but lag is still apparent, though nowhere as much as before when I used scart lead.