Newsletter/Mailing list - with tracking

Hi, I am fairly new to MODx, but I like what I see. I am an "ok" PHP programmer.

I’ve built a site for a client who has now requested a mailing list and capacity to send monthly newletters.

I have looked at (the very little) documentation for Easy Newsletter http://modxcms.com/extras.html?view=package/view&package=120 and TX newsletters http://modxcms.com/extras.html?view=package/view&package=474, and KoopsMailingListX http://modxcms.com/extras.html?view=package/view&package=228

However, I need some advice: my client would like some kind of tracking, so that they know which people/groups click which links in the newsletter.

So I need to know:
a) Of the available newsletter tools, which is easier to customise in order to add a querystring to URLS pointing to the site with a unique ID,
b) How would I go about tracking those clicks (easy enough with pure PHP, not sure the best approach with MODx)
c) How do I go about adding a "results" page to the manager area of the site in order to allow the client to view the data captured (who clicked what link)
d) How should I go about "grouping" sign-ups into categories (manually managed) - again, easy to do via PHP, not sure how to approach with MODx

I think the most complex question is, "how do I add to the manager" (c)?

Sorry if the question is not clear or if I have missed the obvious - I have researched the issue.

I’ve only used EasyNewsletters so :
a) Yes, you can add any sort of link to a newsletter e.g ypour-page.html&userid=39
b)Custom tracking snippet in the page retrieving the &userid value, page, date etc. and writes info to custom DB table
c)Custom module in Manager get DB info from b) view by user, page, date etc.
d)Custom list of user groups with select on registration form
It can all be done, depends on how much time & effort you can put in.
Alternatively you could look at Pommo or another specialist Newsletter program as a standalone solution, or a hosted solution.

Great, thanks- that looks like a good place to start.

(apologies for the late reply, we have had several public holidays)