Amazon part as quoted below. Sound is still raucous, not a purr, but loudness reduction was in the significant-to-unbelievable range at 10 db (80 down to 70) based on Sound Meter app from Google Play Store, with phone sitting waist-high, 10 ft behind the car and centered, closed garage, 2500 rpm.
@Sacto Mitch video sounds amazing and has your preferred dual tips. I should look again at the price of that. Look out for alternatives that require the exhaust be removed to adjust the valves -- that took at least one alternative off the table for me.
If you go exactly the way I went, note you have to modify or replace the rear engine tin to clear the intake manifold heat risers that the Trimil doesn't have.
Have you asked @Alan Merklin or his engine-builder for his quieter-muffler thoughts?
Single-Tip Gt Exhaust, For Type 1 VW Engines, Raw, Compatible with Dune Buggy
|List Price:||$136.95 Details|