Headers are 1 3/4 inch primary with 3 inch out lets. they only come in stainless steel. Ceramic coating is available.
The 1 7/8 inch header is also available for the big head and cam combos / blown cars / strokers.
3 inch or 2 1/2 inch Hi-flow stainless steel cats are a 200 cell metal cat. They have a huge flow rate that suit most cars. Note, if you are running a big cube, big cam or big blower you will need to check with the engine builder, we do make 3 inch cat pipes for race cars.
Dual 3 inch or 2 1/2 inch straight through Mufflers are built with an X pipe, the mufflers are around 1 meter long and hand made to, 1 stop drowning, 2 to keep it straight through.
3 inch or 2 1/2 inch rear Mufflers are straight through, they have a dual 2 inch out let and we also have stainless steel tips for them. The tips come with the a DPE logo.