I got the 3 1/4 inch magnaflow catback system on my 01 z28 and i'am worried about losing low end power couple guys told me i will lose hose power rather than gain, let me know guys i already ordered the system, and its just going on OEM cats with no headers

it should be fine, as long as there's a muffler on it. is this a true dual system or is it Y piped?

just a catback system on the stock manifold and cats

You'll do fine, you still have more back pressure than you need.

especially since there is the stock manifold and cat which will keep it restricted. You should get some headers and a new cat and put a y or h pipe in there.