Eh?
For starters German engineering is often overrated - VW being a classic example.
Secondly Mazda make some great cars - the 6 being a good example.
MX-5 is generally considered to be the best affordable roadster for about the last 15 years.
RWD means that the power from the engine goes to the rear wheels and not the front ones. This is a good setup...power comes from the rear and steering is done by the front wheels. Also makes for a fun drive and the car is very controllable.
It's only stumbling point is that it has a bit of a girly image - but in this case that wouldn't be a problem
For 15K you'd get a very good one - don't get hung up on the year!
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http://www.carzone.ie/usedcars/index.cfm?fuseaction=car&carid=691030)