question if tuning is needed or not..

[0rion]

You might want to qualify that a bit. Of course it doesn't know about a part, and then makes a change. All the MAF knows is the airflow into the engine is higher, from better flowing exhaust, for example. Some people (not you!) forget that these engines are airpumps.

you're right...they are just air pumps and the MAF does show more airflow but it doesn't have any kind of correction factor for parts such as headers.
Lets say you're driving around and your 5% lean in a certain cell...the trimming of the O2's will maintain stoich but if you go WOT from that cell that 5% gets added to your final fueling.
Lets now say you're rich down low but lean up top and you go WOT.....the car will run lean because you no longer have any input or correction from the O2's but instead are running 100% on the MAF.
Hopefully that makes sense....the short answer is you need to tune for mods. Can you drive the car around? Sure, but just because you can drive it around doesn't mean everything is fine. The stock tune is fat and it'll let you get away with quite a bit but if you're going to the trouble of putting headers on a car why not tune for them and have the car run like it should?

[Too Fast]

^^^and you make a perfect point for tuning for any car, stock or modified. Your arguments like the 5% lean in a certain cell can be for any car..............stock or modified.

I've always said tuning is a plus for any vehicle, OE tunes are rather conservative, and you don't have to have one of our LS1 cars tuned immediately just bc someone installed LTs. They drive better after a LT install, usually. Unless we get the "I just installed my headers and now it runs rough" from a loose plug wire connection.

[0rion]

^^^and you make a perfect point for tuning for any car, stock or modified. Your arguments like the 5% lean in a certain cell can be for any car..............stock or modified.

I've always said tuning is a plus for any vehicle, OE tunes are rather conservative, and you don't have to have one of our LS1 cars tuned immediately just bc someone installed LTs. They drive better after a LT install, usually. Unless we get the "I just installed my headers and now it runs rough" from a loose plug wire connection.

what I normally recommend, as do a lot of others, is to try and stack mods before tuning. Don't do headers and a tune then 3 months later add an LS6 intake. Either wait on the tune or wait and do all of it at the same time.