I just cant get into the small scale replicas.
What is a Spitfire without a Merlin?
What is a 109 without a DB605?
What is a 190 without a BMW801?
I agree to some extent, semi-scale aircraft just do it for me. 
The cost of the war-spec engines is prohibitive to say the least but at least companies like FlugWerks (sp?) in Germany are building replicas in full scale with affordable engines... Terribly under-powered, I'm sure, but at least they look the real deal for display purposes. 
It's not like one needs to be dogfighting with Mustangs these days.