We started working on it and are about halfway finished. The quality is OK, the directions are clear, and there is nothing tricky other than lining up the valve train.
I wish the parts hadn't come on plastic trees, leaving little nubs on the pieces after breaking them off. We sanded them down to make it nicey-nice.
Nothing too complex that a 7-year old and a dexterous 4 year old can't help out with.
Overall impression: A fun project, but a bit expensive for a plastic model. If I wasn't interested in Porsche I'd opt for the cheaper Haynes generic V8 models instead.