Fuel pump is a foundation mod and esssential for upping the horsepower ANY at this point. You most economic route would be increaseing boost. After that I know it costs ABOUT $1600 for a set of good installed longtubes. You are going to spend about $1300 if you have your fuel pump installed and dyno'd if it's your first time getting a tune because they have to make it from scratch. It's cheaper to tune after it's made. So your looking at a pulley change for your blower and possibly a reinforced belt tensioner. If you can cool down the air you will find that 50hp easier to get to. Options are out there, intercooler, water-meth kit. Those longtubes along with giving you horsepower have the added benefit of releaving pressure off your motor (healthy), plus they will sound cool, but are pricey trying to get 50hp IMO, though I would love some. Honestly the cheapest way would be a water/meth kit, boost pooley and dyno. I think there is more to horsepower numbers though, I mean how is the car to drive? How does it sound? How is atmosphere inside the car (gauge clusters, shifter)? Sorry I'm rambling and your just trying to get 50hp.