I dont think you realize what you are asking for. First of all, have you ever driven a car with even 400RWHP? If not, then you really need to because I think you will realize that is enough power for right now. Second of all, $4k will get you a blower and tune that along with bolt ons should put you around 400RWHP fairly safely. But then I would highly suggest getting a built block, because if you go much higher than 400RWHP, odds are you will probably throw a rod. A good block from DSS is about $3k+ to be able to handle the power you are wanting to make. And you have not even begun to think of the cost of installation. So that right there puts you above your budget. My suggestion would be this...
1. Get the KB 9psi intercooled kit for $4700 or Cobra Killer's
Vortech/Paxton kit for about $3900 and buy an intercooler, or go through HP for their turbo kit. I say this because once summer comes around and your are running that hot air through an even hotter s/c, or turbo, detonation is bound to happen eventually. That will put you around 400RWHP for either one of those kits. See how you like it, then put the rest of that money away for a new short block and start saving.
The good thing about the KB or turbo is you will hit boost sooner, and it will feel like you are faster than you really are due to ALOT more low end TQ than the Cobra Killer kit. But you will probably be happy with either kit.