As helpful as the suggestion has been to go on the site and build your car, I believe that you have a 23i? So that's not available anymore so you can't do that. But here is the standard spec for a 2010/2011 23i from the sales brochure
Z4 sDrive23i
17" light alloy Star-spoke style 290
Air conditioning, automatic with two-zone control
Armrest – front, centre
Auxiliary input point for auxiliary playing devices
BMW Professional radio with single
CD player (with MP3 playback capability)
Bootlid operation, soft-close
Brake Force Display
Child seat ISOFIX attachment
Drive Dynamic Control
Electric Power Steering with Servotronic
Electric windows – front and rear with open/close fingertip control, anti-trap facility and comfort opening function all round, via key
Headlight wash
Interior trim, Satin Silver matt
On-Board Computer
Panama cloth upholstery
Retractable Hard-Top (RHT), two-piece with remote opening control in key
Six-speed manual transmission
Sport multi-function leather steering wheel
Steering column with manual reach and rake adjustment
Storage compartments in instrument panel and centre console
Xenon headlights with welcome light and daytime driving lights
From £29,695
You may also find a vin decoder helpful to tell you what is on the car. You can also find links to old brouchers and price lists online so you can then compare to the spec list from the decoder http://www.bmwvin.com