If your brother-in-law is not concerned with originality, fit or appearance then let a local shop use their own discretion. If he does want it as close to original as possible, order the kit from Mike at Classtique. If he needs help with the the installation Mike is more than ready to help with a phone call. I have installed several of his kits and they are equal to LB in material and workmanship. They fit well.
Have seen some Cartouche installations. Material was OK. The fit was not. That was mostly due to the seams in the wrong place.
Just so we are all clear, the material that
ALL of us who are sewing interiors use is from Cartouche. Trying to imply that one kit manufacturer's material is superior to Cartouche's is pretty much false.
Mike Francis & I are good friends, -and his predecessor (Elizabeth) and I were great friends too. With that said, there really
is several others who can (-and do) fabricate "closer to original" than those mentioned above. (This definitely includes the former LeBaron Bonney's kits.)
As far as 'fits' are concerned, I have been an authorized installer for both L/B and Classtique, -and from my perspective, Mike's fit & finish exceeds what L/B was producing. As far as seams incorrectly sewn or placed in incorrect locations, ...again most kit manufacturers are not interested in producing 100% authenticity, however, often times the blame needs to be placed on the interior wood kits for being incorrectly shaped, -or the seat springs not manufactured to the correct original sizes.
Adding to what Gary was saying above, there is definitely more to correctly installing a 55A interior kit than watching what is available on YouTube. Most restorers incorrectly install the covers, incorrectly install the wadding, and the list goes on. Experience is definitely your biggest asset.
Bob/Henk, I think prices have kinda gone up some now. To professionally sew and install all of the trim inside of a 55A will generally run about $7,500-$8000. Even a kit today will be $2700-$2800 range by the time it gets to your installer. Then factor all the time needed to do the top and interior, you are looking at 70-80 manhours if you want a quality job.