The MP electronic ignition kit isn't a good choice. It contains a distributor with a single lightweight mechanical advance spring so all the mechanical advance gets dumped in just off idle.
I have no idea what the MP \6 kits had in them, in anycase they don't make them any more and its not likely you will find one. But I found when I was running a \6 in the Cuda that a stock light spring and one of the springs from the MP two spring kit would have all the timing in on a stock \6 distributor around 2500 rpm.
The v8 MP distributors (like the one in the kit the OP posted a link too) since about 01 have been made by Mallory using a factory style housing (unless you get the billet one) with a Mallory adjustable mechanical advance mechanism inside. I have purchased one billet unit and one with the factroy housing and vacuum advance in the past few years. The billet one had two pink springs which with the 24 degrees of advance the distributor was setup with had all the timing in at 2000 rpm. The Vacuum advance unit had an orange and a brown spring that combined with the same 24 degree setup had the timing all in at 2800 rpm.
The nice thing about these MP distributors is the adjustable mechanical advance which comes in handy when you start using bigger cams with a lot of overlap and need to limit the mechanical advance so you can run more initial timing. Mallory sells a nice tuning kit #29014 (also available under a MP number) that comes with an assortment of springs and spacers that makes setting one of this up a snap. The instructions also include a bunch of timing curves so you can select the proper color springs for the rate you want and I have found they are pretty accurate, within 100rpm. The other nice thing is they use a stock cap. rotor and pickup so repair parts are as close as the local parts store.