Gonzo, just put it on your credit card...I need someone to pay my salary!
RReuphoria, sounds like you're at a bit of a crossroads here. The intake will bump you into STX automatically. So there are two options.
1. Stay in GS. If you want to be competitive for the least amount of money, stay here. And while you like knowing how the car handles on street tires, if you want to win and do well (other than locally), you WILL need r-comps. End of story.
2. Install the intake and move to STX. Now you only get to play on street tires, which seems to be your focus. There are a lot of mods you can do in STX, but make sure you only install STX legal mods or you'll be playing in DSP or SM...which you don't want to do.
I think STX is a TON of fun to run in, but there's more tweaking involved and a lot of parts to buy. GS is easy to run in and is probably your best bet for being competitive. But ultimately it depends on what's more important to you: modding the car to your liking, class be damned, or mod to be competitive in a specified class.