The LRP is fine. It wasn't on my list as it isn't current. I suggest you up the timing on the Dynamite to 38 to 40 deg and gear about 65/66mmpr. If it is still cold then time up a smidge. If you like the timing where it is then go up a couple of mmpr.
I don't know enough about these speedos, except that they all use different firmware. I think the reality is that the component quality in these is a bit better than the old LRP SXX v2 hence them being a bit faster in the blink.
The Dynamite motors are underrated in my view. I sold one some time ago and regret it. The Hirosaka motor (Zen Racing) is good, and I have a GForce 10.5 in my 12th car that is also good. In reality it is all about finding the sweet spot for any motor, so sometimes a lesser motor is better than a good one outside that sweet spot.
For a reverse speedo, I'd be tempted to go for the GForce with a program box. Zen will set it up for you when you order so you can get it set just right. However, once you have reverse available it doesn't help improve your driving when you know you can just back out of trouble. Give the markers a wider berth and try getting closer rather than hitting them and backing out, you'll get better, faster.
Yes, I have a degree in Stating the Bleeding Obvious from the University of Absolutely Nowhere! HTH
