something like 430-450 was a justified price. but my own opinion is that if working is good, all is fine. i myself get any scratch fixed fast. its my car, it should look good to me. resale? will see when i sell it :P. own satisfaction is more important than resale. so if it needs compounding and polish, get it done and enjoy.
as for prices, crystal headlights came in later mode. will cost you around 5000-8000. but better clean and use original ones.
get a alpine 2nd hand pre and 6x9 speakers for rear.4-5k for pre and 3-4k for speakers
cheap rims will cost 8-10K and good quality rims, 15-20k. a must for sporty look.
do you mean poshish? it can cost almost 2.5-3k
as for HIDs it depends on quality of hids. cost 3-5k.