My 3.1 N/A with Dynomax (I know, not a 4th gen, but it's my baby)...
A customer of mine with my ported heads, my custom cam, and my OBD1.5-OBDI swap kit, Pacesetter headers and Flowmaster (untuned clip, more to come soon)...
3800 with my ported top end, FFF longtubes, unknown muffler...