Nereus
 
 ^ Wow that Z4 looks brand spanking new! I did a quick search - extremely reasonably priced, I thought they'd be way more expensive. We have a young daughter so something like that would be totally impractical, but yeah fun! Enjoy!
 
 

Prices are awesome, but the condition is critical on the 2003-2009 versions.
There are a few well documented service issues with some very expensive repairs (convertible top motor, HG oil leaks) so you -have- to be very careful.
And lot of these used Z4's for sale have been beat on badly or wrecked, and you do NOT want to get one with "sticky steering".. 
 
Got lucky with mine, noticed the convertible top was slow (bad sign) so before purchasing it I had the dealer -split- the $2100 cost of a brand new motor and new hydraulic lines. It also had (luckily) the cheapest oil leak (oil filter housing). Other than those items, only the control arm bushings needed to be replaced.
All totaled, I've put in about $2000 to resolve any remaining issues after purchasing it. Right now there is nothing left to fix.
This car -does- eat though very expensive tires quite fast, but that's just the cost of driving a high camber sports car that's glued to the road.
 
Not as impractical as some of the other Z3-4 models, bigger trunk than both the older (Z3) and newer (2010+) versions and great gas mileage on the highway.
Biggest daily issues with this car are parking it safely, avoiding speeding and taking care of the paint.
*This is my first black car, and I had no idea that black paint was -so- much work to properly take care of