Firstly , you would be better off being patient and watching the list for coupes that come up for sale and when you see the ONE buy it don't haggle ,umm and arr.
Secondly, as far as Bimmerbros go I am on the fence , They provide a service and should get paid for it. If you inspect the car and are happy with it and what they are asking for it then its on you. They are after all a used car dealer selling 30+ year old cars.Now if you buy it sight unseen based on their description then it really is on you,if you get a independent PPI on all their cars you will know what you are getting.
Lets not get into the public slagging off of companies on this board if you have a gripe PM it to the person with the question , if you have praise for a company then yes go public with it.
We are a very small community here and we do need these people to keep supplying us with Cars & Parts wether you like them or not.