new-96 caprice LT-1

hi, new to this forum, original owner of 96 caprice well taken care of with lots of upgrades to much to list here but anything i put into the car since 96 was quality performance parts and am ready to go internal now with mods and will be searching for advice. presently looking for good quality exhaust manafolds and low restriction cats. don't race but do alot of highway driving and enjoy the power. occasional race on the street. i'll post alot under impala because the car is simalar and those are the upgardes i've been replacing with. so for now anyone that has done a exhaust system upgrade on the impala/caprice and can point me in the right direction, THANKS