I always knew HEP and distributor is not accurate because whenever I use a timing gun to set base timing, the timing mark always jumps between 10 to 14 and never settle on 12.
Now with MS, timing mark is where ever I set it in the software, every time.
After my last dyno, I found I am able to run more ignition timing while boosting on E54 (MS tune) than E85 (LM tune)! Here are the timing tables for both tune.
E85 tune on LM with Turbonator, HEP and distributor. We added timing until no more power gain and power started to drop, then we back off couple of degree.
E54 tune on Microsquirt with 36-1 wheel welded on the crank pulley. Same tuners on the same dyno.
What does it all mean?
With MS, I'm making about the roughly 250 WHP at 12.5PSI, it took 15.5PSI on LM to get the same power.
So, if you're looking for low boost and high HP, I'd say go aftermarket ECU and get rid of the HEP and distributor.