Another exhaust question

1990
stock exhaust except i will be putting a flowmaster super 44 on soon. should i do a highflow cat? i have a speture cold air intake. and i will eventually change my header cause its cracked. it has putty on it now just to pass inspection. my main concern is will a high flow cat make my back pressure too low. i dont have a muffler on right now and it "SEEMS" like im missing torque. will a high flow cat and free flowing muffler make it run like it is now with out the muffler? how about after a new header and front pipe?

Honestly not sure I would worry about a high flowcat. To me the outcome doesn't warrant the cost....

im probably gonna change the cat i just wanna know that a high flow wont make me loose torque.

No, if anything you would gain

ok. so now the exhaust header can i use a 91 and up header on my renix? and will all this be ok with the way it runs? does the ecu adjust to the free flowing exhaust?

The typical XJ exhaust is not free flowing. It is true you have a short header for an exhaust manifold. But that bend and pinched pipe make it somewhat restrictive.

i know it isnt but it will be with the new cat and my muffler and a header if i can find one.