the $2k-$4k will easily cover stage 1 mods! That being - full exhaust, pod, FMIC, ecu (with tune) and boost controller. (i think thats all isnt there?)
Do the basics first. E.g I have just put on the exhaust, next is pod and FMIC - should get me some good power gain. Do them first, then get the ecu etc. thats my opinion though.