I have read that too about the need to be moving at a steady clip to get a reading off of SI. On HB's site there are a series of videos promoting their SI and all of them they are cruising and scanning with the big motor running -- scouting is the way I look at it.

As far as my decision I am leaning towards picking up an LMS-520 with the Navionics chip and putting it up front in place of my X-85. It will be a pretty good learning curve in itself to get used to gps mapping and a color graph. The 520s are still readily available on the internet for $500 or less. Interestingly the 522s (internal gps antenna) are as hard to find as hen's teeth but the external antenna on the 520 is not a problem by me. It is just another install step that you wouldn't have with the internal.

From there I think I will sit back for a while and watch SI units evolve and look to pick one up for my console sometime in the next year or two as things settle and I learn more about them. Prices tend to improve after a new technology gets out and settled for a while and SI units carry a pretty good premium right now...

kc