Hi, not sure if it's too late but thought I'd way in here as I recently bought a 2016 A4, also manual.
So mine is a December 16 (66 plate), was looking for a manual only and ideally a black edition but couldn't find one at the time so went for an Ultra and will get it wrapped soon. Compared to my black edition, I didn't think I'd ever say this but I love the ultra much more. So good on the motorway compared to the BE and good power. It's a strong engine and they don't tend to let you down (others will agree mostly, as with anything though there are exceptions).
My annual mileage is probably at least 15k so the ultra seemed a good idea. Leather seats, more interior lighting/extras, sunroof, MMI is the top of the range so big screen etc. Fuel consumption surprisingly good. Road tax £20 and I believe it is ULEZ if you live London.
As for power, 190 is perfect I believe. I think 150 would be fine if you weren't too fussy and for financial ease but if you had the chance for a 190, my advice would be on that. Good in town for overtaking and on the motorway it really flies! Take this from me who regularly manages to get from Cornwall to the Scottish border in under 4.5hrs and still average about 60mpg. I've had lots of fun keeping up with M2's on the motorway (obviously they could leave me sitting if they wished), but realistically on the motorway you likely won't be going over 100mph and so 190bhp is pretty much perfect.
It's really comfortable. I regularly travel more than 600 miles in a day (stopping only for fuel once for 30 mins) so this is important. Even these long journeys I dreaded initially but I actually look forward to them now. It's like being in a nice hotel room just sitting and relaxing really! Compared to my old A4 black edition - that thing was terrible on motorways and physically gave me back/hip pain after 2hrs on a number of occasions.
Overall, if you do reasonable mileage, go for the diesel. I really wouldn't see the point if it's only in town. I drive maybe 5 miles a week sometimes but then other weeks it's 1200 miles over 2 days so it averages out well for me! If you go for the diesel and you're able to, get the 190. Good fuel consumption, good power, good comfort. In town it does chug diesel, but longer journeys it costs me around £60 maximum to cover 600 miles. Pretty good in my book.
Happy to answer any other questions. Sorry if this was long, just want to help as I know the pain of finding the perfect vehicle for your needs!