i used performance floors in mt Clemens. didn't know about the top coat since they never mentioned it but i do a ton of fab work and the floor has held up better than the previous attempts
my only beef is that there are discolorations where oil was left on the floor for long periods of time and it stained the epoxy but overall I'm happy with the results.
i did it all myself and the cost was around 300$ for material
as far as weld marks well they are there but its not a huge deal to me since it is a garage