I did not usually test fit anything first in the old days when I was building plastic injection kits. That is because injection kits usually can fit quite well out of the box. The problem with these 1/43 white metal cast kits is, they do not fit together well. Parts often need modifications. I did not test fit parts when I built the first couple of 1/43 kits, and I had a lot of trouble fitting the suspension pieces to the body. Test fitting parts, make sure they fit together and getting an idea how they should fit together is very very important. Spending more time up front test fitting things will keep me from a lot of headaches and frustrations down the road.
I made pretty good progress last night and today. Got the transmission fitted with drive shaft and rear suspension. Also, the rear wing is put together. I suppose I can start painting pretty soon.