Well, the NX Gemini kit is a good setup and makes very nice power. NOS makes good kits, adjustable from 75-250 and bigger setups as well. When you buy a kit, you just change the jet(s) according to your power level. On a stock 302, you can spray 150HP all day without adverse effects as long as your air/fuel demands are met. Talk to 5pointOhNo as he's very good with spraying 5.0s, his own cars have very good street/strip success...... I personally like NOS Cheater system.
Before you get the spray, install a 255lph in tank high flow fuel pump, adjustable fuel pressure regulator, upgraded ignition system with coil, and get the appropriate spark plugs. Don't forget to lower the initial timing when you spray.
SS