Exhaust in the making

Exhaust will be 4-2-1 with 3 steps and 3" exit. First 90 degree bends 1 3/4" then 1 7/8" to the first two collectors and 3rd step 2". I'm not quite sure how it will end up but I hope it'll be OK.
2 1/2" to 3" 90 degree cone. Made from two 2 1/2" bends.




2" collector completed with the cone.

1 7/8" collector.