Again redrumracer sir, there is no substitute. A T25 lags, takes away throttle response, and unless it's a crazy 50,000 dollar race car engine, you aren't safely revving that to 9k for extended periods of time. Supercharging is good, but it's just the beauty of a raw naturally aspirated screaming engine. Not to mention I bet a T25 turbo Miata would lose to a NA Miata around a road course.

Also a turbo does not offer predictable power all through the powerband.