I popped to Colchester the other day and was on an 8-car 321 between Manningtree and Colchester, sat in the coupled cars and the banging and clanging was incredible. My thinking is surely if you have 2 units with different acceleration capabilities, surely this will be even worse?
As it happened I caught a ride on 321303 from Harwich to Manningtree the following day and can honestly say, when it accelerated (what seemed) fairly hard between Wrabness and Mistley, I noticed no appreciable difference in acceleration, but that was obviously only up to around 60mph. Obviously I don't know how hard it was being pushed, but it didnt seem an awful lot different. It didn't thrust me into my seat like a 360 but maybe I'm expecting too much. However, the Interior seems nice, Disabled toilet door was broken already but all in all, I like their work.