I agree with most of what was said above.
Superchargers offer mind blowing instant torque at a cost to operate.
Turbos offer greater horsepower gains due to very little cost to operate.
The drawback to turbos is engineering the system to reduce lag and the complexity and weight of the system itself.
Superchargers are fairly uncomplicated with less plumbing needed.
My take is that if you want a stoplight hero bolt on a whipple/roots supercharger. If you want a top-end monster go with a turbo.
Also, if you plan to run a 915 you might want to stay away from the whipple. It produces full boost by 1500rpm to redline with torque levels that are very painful to the 915. With a turbo it is not so easy to stay in boost between shifts. A whipple will allow shifts like a big block Chevelle, lots of tire smoke.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8