There is a super charger kit for an inline. But I think it illustrates my argument for a V-8.
Once you add a compressor you'll have some significant expense for modifications plus you'll be running premium gas.
I've not seen a turbo setup for one of our six's, but I haven't been looking either and it would be the same story. Lots of money, premium gas, and still have trouble matching the power output of my stock big block.
It's not that everyone should run V-8's, but that if you really want performance you'll get more for you dollar with more cubic inches.
If you want cool the six can be a very good answer. If you start out by wanting to win drag races, other things being equal a big V-8 is the answer.
Another great option for cool has to be a big Buick V-8... I have one that may end up in one of my projects some day.
Before anyone jumps on me, I need to remind you all that I drive a GMC 270 on those days when I don't need to relive my youth with the big block.