I agree it sounds like a good deal. On the matter of rust try to get a look up under the at the rockerpanels, the plastic cover does a good job at hiding the potentially expensive repair.
When you say it cuts out at 5000 rpm, does the engin stall or is it the rev limiter, or does it just have no power? It might be a vanos issue?
I paid about $6000 for mine Jan 2010, with 192K at the time. So you do look to be getting ahead so long as you don`t have any major issues. One thing to bear in mind is that being an OBD II car is that some of the electronics are not interchangable as they are vin specific. (the instument cluster for one)
Please keep us posted.