yes you should have it R/R straight away to get an idea of what power you were making then could now R/R and see if it has dropped off, i doubt the power has gone anywhere my guess would be that a flat spot has developed and made the car feel slower/sluggish.
a session should show up any flat sopts etc
what gains did the company quote you would acheive with there re-map?
may i ask what company?
.... But I now have a M3 CS