Plugs/wires and exhaust question (removing muffler)

[truck]

I just posted a thread under the intro section since I'm new here, but what are the most ideal spark plugs and wires for the 350 vortec? (I am assuming there are better spark plugs than OEM) It has 204k with a rebuilt 4l80e

Secondly, the truck has dual exhaust setup with tips, di/do flowmaster and stock cats. Will replacing the muffler with pipes affect anything performance wise? I've read over the years that removing a muffler will affect bp, yet stock cats create enough bp that it wouldn't matter...?

I'm sure there are a ton of threads about this, but if someone could put their two cents in or share a link to a thread, I'd appreciate. Thanks gentlemen!

 

[SCOTTYINWV]

AC delco iridium plugs and descent set of wires will be plenty. I prefer at least 8mm wires, but don't even see any difference running wise.

I would swap out stock cats for some higher flowing ones and some different mufflers. Do you know what size exhaust it is?

 

[truck]

Unfortunately, I can't go with high-flow cats cuz I'm in CA. Stock cats only or it won't pass smog, and it's not worth swapping the exhaust in and out each time I smog it. I believe it's 2.5" piping, does that even matter?

 

[IOWNJUNK]

I'm a Flowmaster fan so I would leave the muffler as is, gonna agree with above on ac delco iridium, not that they are any better than others, just what I use. Nothing special on wires, just whatever exact fit set they hand me over the counter. 2 1/2" duals is plenty for your motor.

No high flow cats in Cali? Didn't know that. Of course it's probably like that everywhere, no smog testing here.

 

[truck]

I respect that you're a Flowmaster fan, however the muffler that is on the truck is old and sounds like it simply needs to be replaced. I'm thinking the cats provide enough sound dampening so I might as well replace the muffler with pipe.