Mike (Red Baron) would have a good amount of info for you on this as he had a carb setup in his rabbit truck.
I purchased most of his stuff with the intent to put it into my Rabbit but I had to sell the Rabbit for school money and who knows when I will find another Rabbit. Who knows, maybe I should sell it all.
Onto the info you need....
I will post all my links at the end.
Yes you need a special saucy manifold. Pierce manifolds makes the best one around . Available here...
http://weberpartsdirect.com/ The manifolds are really nice and aren't pieces of shit.

Weber 45s seem to be the best size carbs to rock. Most guys I have seen run these carbs due to the fact that with proper jetting they can be very well suited to either 1.8 or 2 liter 16vs. Plus they are abundantly available, easy and cheap to repair, and parts are available all over.
The MSD 6A works but the 6AL is the better choice. I can't rememebr why. I think it had something to do with the ability of advancing and retarding the ignition timing. The difference between the 6A and 6AL is only one thing.
Carter 4070 is the way to go. Just the right amount of fuel. Summit has them For $70.
http://store.summitracing.com/partdetail.asp?autofilter=1&part=CRT%2DP4070&N=700+4294925239+4294839053+400415+115&autoview=skuIf you are goign to run the webers, you need either an ABF waterneck or a nice machined waterneck from here....
http://www.twminduction.com/Home/sitemap_FR.html. It's not on their site, but they make it.
Mike ran filters and horns for equal amounts of time on the street. Neither gave him any problems. But getting a rock in a horn wouldn't be good.
Here is the setup I have sitting in my garage....


Here are some links that may help you out.
http://www.webercarbsdirect.com/http://weberpartsdirect.com/http://www.racetep.com/webtechpage.htmlhttp://www.carburetion.com/http://www.redlineweber.com/http://www.4secondsflat.com/Spark_plug_reading.htmlhttp://rotaryracing.com/ff_watercooled.htmhttp://www.twminduction.com/Hope that helps.