so get an aluminum 4 cyl. and 70 lbs is quite a lot to add to the nose of the car. especially if you're t/cing after you put the KL into it.

 

i think that mazda engines can make power in N/A form, you just aren't looking the right place. sure it will be expensive, but what you're asking is an expensive task.
example
buy a 1.8 miata (aluminum block if memory serves) and call up toda racing. after you've spent several thousands of dollars you'll have an engine that can make 250hp N/A. it's not that tough. where is MM? there are 2 600hp mx6's one in florida one in texas. i've ridden in the FL car and it's a pleasant drive. FE3's are locatable, just as much as any foreign engine, which if you want to go all the way with a KL and get the ZE version, you have pretty much the same difficulty. for a BH series car (the one in question) you guys are going to have to wait a few months. why? because due to the fact that the GE (2nd gen mx6,probe) cars had the KL in them, the FS was overlooked. But now there are FS's making 220hp N/A, although granted thats in race trim, but it's also using fuel injection, which is not the best for a normally aspirated car.

 

Get whatever you want and can afford. The FE and F2 engines have larger bore spacing and deck height than the FP/FS engines. They would probably be harder to fit in the 3rd gen engine compartment than the KL V6. Neither of them would be easy, so most likely you'll just have to be patient and wait for more R & D on the FP/FS engines. So far, they appear to have very strong bottom ends, so there is potential.