A pair of aluminum exhaust tips with an angled flared end.
This is hollow and looks realistic.
Inlet Diameter: 1/8"
Outlet Diameter: 3/16" (flared end)
For 2-1/2" exhaust pipes to match, use .112 aluminum hard line. This is almost the same OD as the tip OD, so file down the end a little where it inserts into the megaphone tip.
Here's how it would look with the aluminum hard line.
Two aluminum pieces by Parts by Parks, 1/25 scale.