sounds like he's already got a suspension planned/budgeted, and is looking just for the motor at this point (which, btw op, ditch the 17x9 rear idea and go for a 15" combo with more sidewall for track duty, stick-shifts and dr's, especially low-profile, are real tricky to get to work together).
on point, for 4.5k....vortech kit and maybe a different cam would go a long way, and would be the simplest, most proven way to add boost (those vortech kits have been around since the 90's, i dont even think they've changed the kits other than phasing in the newer 'chargers themselves). if you go used, you should even have enough for a bigger intake (systemax2/performer rpm/tfsr), and maybe some longtubes (which you WILL want at least eventually).