Concentrate on getting the car to run right and reliable for now.
Since you are changing the cam to a tfs with springs you probably should be in the 250-265rwhp.
Get to know the car, learn how to drive it.
260rwhp may not sound like much compared to new cars, but a fox with that much power may bite your head off if you don't know what your doing (even worse if you think you know what you are doing).
260rwhp is also alot on a fox suspension and brakes, if you don't work on that next you will have a sloppy mess of a car that you need to have towed out of the bushes.
Unless your pockets are very deep, for the moment, stay away from power adders, that goes for an SC, turbo and even nitrous.
Rome wasn't built in a day, you need to grow with a foxbody mustang, not just one day you have 190rwhp and the next you have 400, that's a recipe for disaster.