hipster: Its smart to ask for the advice, selling your pride and joy can be a painful experience. I was horrified that I could only get $12500 for my absolutely beautiful '92 nissan silvia turbo. It was worth so much more in my heart.
I was also amazed that I could not sell my Nissan Pulsar GTIR for anything over the $16k mark, and only just recently sold it for $15,800. Trust me: Its not worth having a car for sale for 6 months.. after about month 7 you just want to get rid of it, and then you might do something stupid like take ANY old price!
I would recommend stripping the cars stereo and as many modifications as you possibly can, and drop the price down to the mid-to-high teen mark. Having these items lying around on your garage floor also makes great negotiation tools once the buyer has test driven your car and its time to talk the sphincter of the universe. Throwing in a set of speakers or turbo timer etc. is a great incentive for them to buy your car over the one down the road..
As I mentioned before, you cant expect other people to pay for your mods. A lot of buyers are looking for a stock standard example because they are believed not to have been thrashed.
And as RB30 put it, put yourself in the buyers shoes.. what makes your car worth $5k more than the others in the buyers eyes? I imagine most potential buyers would rather spend the change on mods
Yes, there are other Series I r33's for sale for the high teens to early 20s mark, but theres a good chance they've been rotting on the carsales/carpoint/tradingpost listings for over half a year... And if you see them dissapear that doesnt mean they got sold for asking price.