If someone links to me with "keyword word" or "word keywords" rather than just "keyword" does it have a negative effect? For example, if I'm trying to optimize "ferrari" and someone links to me with "ferrari enzo" or "red ferraris" is that just as good, or not?
It certainly isn't negative because its still a link. Having different anchor texts actually make it look more natural, but having more links with one exact keyword may help you rank better for that one keyword.
I think it's a good idea to mix things up. It certainly isn't going to hurt you but try and pick 3-4 keywords..maybe 1 that is pretty easy to rank in..then 2 or 3 tougher ones. Then mix them up when exchanging links. If there is 1 main keyword you wanna go for use that one more than the others
If you are getting those varied anchor texts, it also helps to make sure you use that varied text on your actual page too. Matt