I swapped in one of these DC CDIs which does work with the TNG Lowboy. The idle seems a bit better, but the top end lost at least 4-6 MPH which is odd:
http://www.ebay.com/itm/282340029624...%3AMEBIDX%3AIT
I am guessing you can adjust the pot on the unit, but I am not sure. (no instructions came with it)