I think 3 grand to achieve 450bhp is seriously ambitious to be honest.... Infact you could quite easily spend that on a decent full exhast system, CAI and engine management which is unlikely to take you beyond 350
Some more experienced members will be along shortly I'd be surprised if anyone has achieved 450bhp on a normally aspirated engine.....I know that nitrous could temporarily deliver a 100bhpshot in theory, effectively giving you 400bhp but I cant imagine it would be long before the engine went bang