Hi Gulliver1
TBH with that amount of millage every week you'd be mad not to go for a diesel. I had an E36 318is which I used for commuting everyday 75 miles to work and 75 back and i had to put over €150 into everyweek plus toll bridges for €29 per week which was ridiclous. I then traded it in for a 1.9 diesel golf non turbo and do the same commute for €60 diesel and with money being tight I use the back road instead of motorway therefore saving a further €29.
To answer your question a 1.6 would be just as hard as the 1.8 and being an E30 it will need a lot of work, if it hasn't already been done. My friend is currently replacing all the suspension, roof skin as there are little water channels that block up with dirt over the years, arches, complete brake system and doors. I defo consider them to be a really nice car to drive and all but in our current climate money talks.
Hope that help and sorry for all the negatives about it.