Get one, get one, get one, that's all I can say.
If I had £40 or so to spend on my car this is what without doubt I would spend it on.
It idles MUCH smoother, starts MUCH better, pulls MUCH better low down.
Don't ask for downsides as there aren't any, unless you count ten minutes work to chop some wires about, ie puit on some different terminals, it even fits in the same place as the std one, with the same holes.
The only odd thing is finding the + and - marks, they are between each pair of terminals.
Honestly other people who have fitted them have said to me it is the best mod for the money they have ever done.
Just make sure you use decent leads plugs to take FULL advantage of it.
My sapphy pulls from 850 rpm in TOP without moaning, not like a rocket obviously but amazing you leave it in higher gear longer and it pulls harder, when I have been overtaking things I have gone to grab 3rd gear to change up and missed as it was already in 4th.
It really is so much smoother.
tabetha