There are a few issues, such as volt drop in the primary feed cables and lengths of plug leads.
The Thor coils are a pain to get to, but generally you don't 'need' to be at them that often, and I try and arrange anything in that area to coincide with a service or repair to something else.
If I 'had' to do it, I'd split the packs from their bracket and mount them one each side so the plug leads are kept reasonably short.
Peter