I have a brand new 2008 1600 Mean streak. What is the best performance mods for these bikes? I was thinking a set of Vance& Hines pipes, a K&N air Filter and one of those D-Boost Chips.

 

AK, it kind of depends on your budget. If $ is no object, I'd go with a bore kit, new knife-edged and balanced crank, mill the heads, titanium con-rods, tune the exhaust ports, etc. Then I'd go with the V&H pipes, K&N (or BMC), and spec the available chips.
Sounds like you have a very nice bike, about to become much nicer!
(Post some pics!)

 

I am not sure on the performance items for this ride. I always concentrate on the suspension and handling first. Enjoy the new ride.