hmm for 5k your really looking at a charger, i'm currently looking into a 1G or 1JZ conversion and it's set to be around 7-9k depending on how big I want to go, my goal is 400 at the wheels so i'm looking at a single. Only problem on the 1JZ is sourcing a R154 gearbox but your better off just trying to find a manual soarer/chaser with the 1JZ lump :)
My other option was a RB20DET swap to be really different which is not out of the question but due to the manufacturer it will cost a little more due to the pig of an issue that will be the electrics.