Well, I love the idea, the fabrication leaves alot to be desired though.
If he can get the front suspension geometry correct, that should be a very fun car. He may want to swap to a lower numerically rear gear also, I wish I could do the same with my 3800 powered FC but 3.90 is as low as Mazda went.
I can testify to the durability and performance of the 3800 engines, mine has seen 7 trackdays without the slightest hint of a problem and runs quicker in the 1/4 mile than a TII.