Need help

I've been approached by someone on the west coast about buying my F355 spider. I have entertained the idea of selling it from time - but I love this car. I have the car setup perfect and it is on the cover of the 355registry. Need to get some insight what she is worth. Forget the market conditions - it isn't a give away, but a "fair" sell for me to even consider:

It is completely sorted:
1998
grigio titanium/black hides
6 speed
24k miles
challenge grill
scuderia shields
hyper flow cats
tubi exhaust
stebro headers
k-40 radar
euro front parking lights
kevlar clutch
major Jan/06 -5k miles ago
new Mich PS2s
fluids/filters 500 miles ago
Interior - dash is great condtion, all leather exceptional, sticky parts
repaired and/or replaced door handles
refinished seats - no wear, no bolster wear, no cracks
paint excellent
factory car cover
tools, all keys, books and leather case