SRT has roughly 349 crank HP which is alot different than RWHP. I do not think anyone has a Crossfire with 450 RWHP that I know of. The mods you are talking about should put you in the 330 to 340 RWHP range. Remember, crank HP is for marketing only. RWHP is what you use to measure usable HP.

If you are talking 450 crank HP (which, I am not sure why you would want to), you would need to mod to approximately 369 RWHP which is achievable but not with the mods you described.