which one holds less heat,aluminum or steel? does stock piping plastic hold less than both of these?

also found powder coated...whats this do?

tia

2005 Corolla XRS
2ZZ 6-speed

Well..

in order of heat retention, least to greatest::

aluminum

steel

plastic

plastic being the worst, aluminum, the best.

<edit> powder coating reflects heat

FS: 2.5" Test Pipe 25 shipped

i think your thinking of ceramic coating reflects heat, powder coating is basically just a colored coating.

HOW POWDERCOATING WORKS:
Electrostatically charged powder will adhere to a grounded metal part. The part is then heated to 350° - 400°F and the powder melts and "flows out" forming a durable finish upon cooling.

dsm/mitsubishi service manuals https://www.mediafire.com/folder/5k14qlaulb9s1/dsm_mitsubishi

service manuals(my whole collection) https://www.mediafire.com/folder/ac51jwwa3g1n1/automotive_manuals

the ebay ad says it reduces heat.

arent AEM's powder coated to reduce heat?

2005 Corolla XRS
2ZZ 6-speed

yes they powder coat them, no its not for heat. mine would get so hot i couldn't even touch it, i sprayed it with clear coat with ceramic in it. it helped keep it cooler but it still got hot.

dsm/mitsubishi service manuals https://www.mediafire.com/folder/5k14qlaulb9s1/dsm_mitsubishi

service manuals(my whole collection) https://www.mediafire.com/folder/ac51jwwa3g1n1/automotive_manuals

powerder coating is abasically charging the "powder" or paint to the object to get a clean easy finish that is fairly durable for mass production... i sued to work ina powder coating shop, yes it is heated to 350-400* no it does not reflect heat at all

You can have it cheap, fast or good. Pick any two.

If you want it cheap and fast, it's not going to be good.
If you want it cheap and good, it's not going to be fast.
If you want it good and fast, it's not going to be cheap.