I've always been curious on either a small V8, as in, Dino 208 GT4 small. Itsy bitsy 2.0L V8, amazing sound but you still have to wring it's neck to get any appreciable performance out of it.
I've seen a lot of MX6 swaps using the 2.5L KLZE V6 engine. A few people have calimed and documented the entire car having no change in weight, some even claim the car's lost weight with the swap.
Considering the V6 engine are all aluminium builds, it wouldn't surprise me...