It's not the prettiest of set ups but is functional. Never had any issues with water getting in and driven in some very prolonged wet conditions as well as snow. One day I might get round to "tarting" it up, will never look like your engine bay though. I have just found my notes from when I did the tests and have slightly exaggerated the gain it was actually 4.92%
Function is always the first priority. Frankly I often get embarrassed about my engine bay (bling!), but it IS a fun place to spend a day.
My wife thinks I am cleaner AFTER! 
I have never seen anyone get distraught because their plenum isn't shiny enough, but the same people are dismayed if their engine stops working.
On that subject, if we adopt a non-diagnostic approach to your friend Grump2's issue (I have learned to prefer a step-by-step method as it is ultimately less frustrating) he might have a VERY common problem. The thermisters (one or the other)..little senders that read fuel temperature and coolant on Hotwires, could have gone south. I wrote an article about that decades ago, when a late good friend, Ed Herman, got stalled with it.
https://www.gomog.com/allmorgan/StepperMotor.htm#Stalling Sorry, the pics aren't working and I have no access to GoMoG administration at the moment. I am WAY off in the woods. It is likely one of the two. One is screwed into the fuel rail and the other is screwed in (nearby) into the intake manifold.. Not hard to find or exchange. On a difficulty level, it is a 2 on 10 that will save him a small fortune at any LR or Morgan dealer. Most mechanics weren't born when his car was made and modular manufacture and thinking isn't as insightful. He should swap in the fuel temp one first.
Definitely worth a try. It is about time they both failed anyway.
Fuel Thermister https://rimmerbros.com/Item--i-ETC6661P (they are cheaper from other sources but I like Bill Rimmer)
Coolant Thermister https://www.ebay.co.uk/itm/332398094307?epid=248659015&hash=item4d647867e3:g:HPQAAOSwTLlZ0Wya
Lorne
