i've been quite quiet so far, but in all honesty, you sound like a complete dreamer.
think through what you want to do, your requirements, how much you want to spend. the ONLY way you will reduce running costs is if you find a more economical, cheaper to insure and service car.
a new 4.4 v8 m3, or 2.0 turbo tts are not going to better a rs 200 on mpg (tts might on a run) and you keep mentioning the value of the car. i think it's amazing that you can get one of these for 6k, i really do.
and service the ****ing thing!!