I tend to disagree , the MSD only multi sparks up to 3000 RPM approx where the powerband starts so to me it is a waste of $$
I used 4 FBO systems & had trouble with every one of them , replaced all the components 1 at a time & they ran better with other parts , ECUs etc failed
If everything is working properly the stock ign is hard to beat , high output coil , low resistance spiral core plug wires , reluctor gap set properly [you have no clue how often this is missed , I see it all the time !] good cap with brass contacts , good plugs gapped correctly , We dyno tested all the plugs available for an SS/D 426 Hemi & the cheapest plugs made the most power so Champion or Autolite , the more expensive the plug the more power lost . Make sure the dist is working correctly & is set up properly with a shorter advance curve around 20* so you can set initial timing around 168at Idle & total advance or 36* or so , also the spring have to be the correct load so the curve is early enough but not too fast . I never use vacuum advance on a street car it is more for emissions than power & I consistently improve power & fuel milage without vacuum advance , getting mid 20 MPG from 440s & even getting 18 MPG from a dynoed 440/512 stroker making 400 RWHP & 460 RWtq on a mustang dyno which read the lowest of all the dynos .
You can spend a Lot of $$ & see zero gain in power , the new Rev-N-Ator is claiming power gains but I have yet to test on a dyno with one .