I never trusted em.. i had a 6 box in my 66 new yorker though and it helped a ton and held up.. I could see MSD at the track but my main goal when i build a car is to never need to call a tow truck.. so.. MSD doesn't work with that mindset...
I'm a bit insane though, in the trunk i will have a spare points dist, fuel pump, duct tape and small toolbox :)