Big block exhaust is still loud

Taking the vehicle out of the shop will not change the level of noise at (or close to) the source, as the noise is the noise.
What will change by going outside is the perceived level of sound in the car or at any distance from it. IF that change is enough for your comfort or expectations is entirely subjective and up to you to decide. I wouldn't go through the expense of making more changes until you (1) listen to it outside the shop, from inside the car and standing nearby. (2) listen to it as you are driving it. (3) listen to it as a helper drives past you driving normally. and (4) Drives past you while getting on it.
Then make any changes you feel needed. Maybe you only need to stay out of the pedal when driving through neighborhoods.

Flat panels (walls) reflect sound. Flat parallel surfaces (2 side walls) bounce sound back & forth between them. A square cube of a room is the worst, a rectangle not far behind. The size of those walls will determine which frequencies are affected more than others. Corners reinforce (amplify) lower frequencies (single corners, wall to floor, wall to ceiling, wall to wall,) and even more so at double corners, (wall-wall-floor or wall-wall-ceiling)