First off if you have $4K to spend, don't waste it on this. Cause if you do get the 65% more HP that your tranny will take a sh*t, and you motor ill be running on borrowed time if it is indeed stock. Upgrades like that require custom tuning, and custom design, no matter how easy they say it is to "bolt on".
If you are looking for th cheapest bang for your buck nitrous is about it. Even then you are pushing it alittle. If I had $4k and was serious start from ground 1 and build it up right to support whatever will be thrown at it. Start with proven things such as cam and heads that will not only crate power but also reduce potential knock problems. Get the air in fast and get it out fast (intake and exhaust). Lastly then support the system that propels you (built uptrans and tires). Then go shopping for a upraded SC, or turbo system. Until then nothing comes easy for cheap. That system looks interesting but looks like a overpriced tornado to me.