Definitely an improvement but a pig to set up in some cases. The benefits are limited to how well the mechanical advance mechanism works in your distributor unless you opt for a mapped system without a distributor.
Simplest option is an electronic ignition setup from a 1300 Uno (non-turbo). All you have to do is swap the X1/9 shaft over to the Uno distributor head (otherwise it is too long and wont fit in the engine bay) and bolt the whole thing in complete with wiring and module.
I wish I'd know about this when I did mine - I went for a lumenition optronic system (at relatively great expense). A very good setup all the same though so I shouldn't complain from that aspect.