Best first mod is 4.30 gears Then Longtubes and exhaust Followed by short runner intake. There is more that can be done, but will require more $$
As long as you stay away from the piggy back style (like the BBK) and go with a true dedicated dampner, you're good to go. The March and Steeda ones are great and not very expensive either. If it's just a summer car, I would consider an electric water pump to free up some power as well, but at $300, they're not all that inexpensive.
Yes, the pb ones suck. I know there have been a few motors that went because the oil pump gears let go due to the UDP's(mainly piggyback ones) and high rpms.