Any program you install that has networked communications will open another potential exploitation. VNC is not known for being highly exploitable and you can do a couple things to make it reasonable safer. Change the default port it listens on and use a strong password.
As for a couple of your other earlier questions:
1) can you make your own kvm cables? many times you can not but it depends on the kvm solution you buy
3) Raritan is a very good brand but expensive. Belkin is okay cand can be relatively cheap cheap. This one,
http://www.techimo.com/forum/showthr...threadid=60510 , is very cheap and works okay. Also do a search in the
Online Deals and Coupons forum to see other good buys
http://www.techimo.com/forum/search....der=descending