I think they do sell a cheaper one that they recommend staying under 9:1 compression with. I have no idea what the difference is between the two, but I would make sure the part number matches the one I posted before you buy it.
Really!? EEk, I had heard of problems with sn95's and HI-6. Techincally LOW5.0 and my car's engine is very different. Which MSD did you buy 69clark? What problems did yo uencounter with the crane?
I bought the MSD BTM unit. The problems I had with the crane unit seemed to be weak spark with only 6psi boost. I had to tighten the gap considerable. With the MSD I was able to open it up.
Another problem which I don't know I had with the crane until after I switched to the MSD was this. I run the tweecer with datalogging and I always noticed that the car would pull timing out at higher rpms. I couldn't tune it out and the timing didn't match what the spark tables said it should be. At the time I didn't associated this problem with the crane box. Then I upgraded to the MSD box and the timing problem was gone with ABSOLUTELY no other changes. To this day I don't know way that was happening but the proof was in the Datalogs, so I couldn't argue it. I still doesn't make sense to me fully why it was affecting the spark curve through the computer, but its enough for me to give the vote to MSD. Besides they are the top ignition company out there, hands down.
Its all in what works for you. If you do a search you'll see that 5000 people have had problems w/ msd and 5000 people have had problems w/ crane, and there will also be 5000 people praising both of them. I searched both when I was deciding on mine and it seemed like more people had problems w/ msd + summitt was running a sale on the crane hi-6s so that what I went with and its been perfect, no problems yet in about 3 yrs. of running it yet on my supercharged application w/ the plugs gapped down to .032"
Good luck!