I did the coil-spring conversion a few months ago, buying the springs from
s-racer.com (who I think supplies them to everyone who sells them).  I put
hi-lo's in at the same time, making the total spent just under U.S. $500
with shipping (to Portland, Oregon).  I did not change my shocks, since they
were fine and I'm not doing anything performance-wise.

The front had been lowered by the previous owner and I definitely felt the
bump stops especially at freeway speeds.  My first impression upon
completing the conversion was that it rode like a limo in comparison!  (I
used the softest "blue" springs all around.)  I continue to be very pleased
with the conversion, and the ride is oh-so-comfortable now.

Perhaps I would have had a similiar increase in comfort just by raising the
front end to normal height and keeping the rubber springs - who knows.  All
I know is that I'm very pleased with the result, and am especially glad to
know I'll never have to get in there and replace the rubber springs again!

The front was the biggest hassle - as with replacing the rubber cones there,
you have to remove the upper suspension arm, and the access is a little
tight trying to get the nuts off the pivot before removing it.  The rear was
quite easy - you might want to start there if you haven't played with a Mini
suspension before.

Regards,
Geoff