The ready to run distributors I found to be rather disappointing. I had nothing be issues with 2 different ones. I wound up doing the msd distributor and the 6al box. Yes expensive but car never ran so good.
Well hopefully you get a good distributor, might take some time with a timing light, and see how much advance, and how quick you are getting it. Check the reluctor gap, and check for endplay as well.
At least they give you 2 45 degree boots for the rear plugs.
As per their ad, you should have no problem with firewall clearance.