I should say that have no connection to 123 because this sounds a bit like an ad! But I'm very pleased with it. The one you describe had no appeal to me but they now have a programmable 123. You plug it into a laptop and use their software to put your wanted advance curve using about 10 engine speeds. It was pretty simple.

You can put in 2 different curves and switch between them by putting (or not) 12v to one of the leads. Dead easy. Now you can play with ignition curves on the dyno. I haven't done it yet but I'm planning to soon.

I put one in my 142 a couple of months ago and did a nav rally here in NSW. That put about 1000kms on it and no complaints whatsoever.

I got mine from a bloke I know in the UK when I was there in May but the Australian agent does have them. I couldn't find them on his website, but I emailed him and he did. So I bought a second one to go in the rally car when we put it back together for the Trans Am - although the Corvette idea is more than tempting!!

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JohnH, Sydney, Australia