Realfeel or LeoFFB?

Hi guys, i have recently purchased a G25 and whilst i have absolutely no problem with the quality of it i have to say i do find it very "twitchy" to drive with, i only use the 1979F1 mod here on HSO so have very little experience with other mods, therefore i am not sure if its me, the wheel or the mod, i have had a little tweak around with the settings of the wheel, not really knowing what i am doing i have to say, and it has taken some of the edge off it but it is still a very twitchy drive. So here i am, i have seen Realfeel and Leo mentioned in various places and have had a quick chat with Kimmo about them but can anyone explain roughly what they are, what they do, are they tricky to install and set up, would you recommend either of them and most importantly will they improve my lap times. . Many thanks guys, Chris.