Bob, i was kidding about Challengers
And i have couple Tamiya kits with engine and couple without. They are all great kits when you look quality and accuracy. But what is point of make beautiful model kit without engine, witch is most important part in cars? I dont know about Enzo or FXX kit because i am not interested to buy them, they are maybe better engineered when compared to Revell Mercury or Nova, but ill still like those Revell kits better because for me its more important that i like that subject! And i am not "professional" model builder who always look first what is wrong in model kits and then whine about that everywhere. I am just happy amateur who enjoys building even when model kit its not perfect accuraty.
Now those were just my opinions with my bad english, so nobody must not take them personal. Cheers...