I may add that I'm running fglrx on mobility radeon 3650 with xserver 1.6.3 and synaptics are there and working.
So, it's not that You need 1.7 to have synaptics
P.S. I just can't figure out (didn't try much) how to improve performance with fglrx in KDE4...
that is X fault. X was broken for Intel graphics. If you want a fast desktop, you need to unbreak X. After doing that, it flies.
get the sources for xorg-server, patch them, compile them, install them. Very easy with gentoo. If you are using something else - search your distros forums/mailing lists. I am sure somebody has done something about it.