Hi,
Sorry to hear about your mishap. The M30 is rather unforgiving when it comes to overheating so the first thing I'd check is whether the head gasket has blown. This may be causing compression loss and associated problems.
Even if there is no coolant in the oil or vice versa, the gasket can be blown. I had it do that in six places once when my fan belt broke. In the few seconds it took to pull across five lanes of freeway and come to a stop, the damage was done. Engine ran just fine actually but wisps of steam were coming off the head/block interface in six different places.
Run a compression check as the first step.
Regards,
Adnan