T409 is the grade of stainless steel, dunno what the laser bit is
and be it poor stainless at that heres a quick bit of info for u all regarding 409 stainless steel
MBRP's service and technical teams have been getting a fair number of calls and emails from people who purchased T409 XP Series exhaust systems. After about a year the customers are noticing what appears to be rust on their “stainless steel” system. They are understandably distressed.
For this reason, it is important to understand the difference between T304 and T409 stainless steel.
There is a reason that the Pro Series T304 systems cost more than the XP Series T409. The Pro really is a more durable, higher quality stainless steel. It all starts with what goes into the alloy that makes up the tubing.
What makes stainless steel “stainless” is the addition of chromium to the alloy. Chromium creates a film that serves as a buffer against corrosion, even when it is cut or scratched. The more chromium there is in the alloy the more resistant it is to oxidization or corrosion. The addition of nickel to the alloy enhances this resistance.
T-409 has a chromium content of between 10.50 – 11.75 percent and a nickel content of .50 percent. T-304 has a chromium content of between 18 – 20 percent and a nickel content of from 8 – 10 percent. In fact, there is so much chromium and nickel content in T-304, and so little ferrous material, that a magnet will not stick to it.
A Pro Series T-304 system will not rust or oxidize. It will develop a golden color over time when exposed to high heat. XP Series T-409 has enough ferrous material in it that it will show surface oxidization, especially when exposed to salt or calcium chloride. This oxidization can be buffed off with stainless steel cleanser and a scouring pad ( i like this lol get under car too clean of the salty winter deposits). Rust through will not occur until well past the warranty period even under the most severe conditions( we live in england not the sunshine state in the usa )
basically if u want shiny go for 304 if u want cheap but stainless go for the 409