If your dont plan to remap, it wont be called Stage 1. Just plug-n-play.

Go for Supercircuit. Its abit pricey, but then it has serve me well for 4yrs already. No issue. No CEL on install. But when you data log, you will see a error code on the sensor. It is normal because the O2 is reading wrongly. But it wont trigger CEL because is small issue. Go Supercircuit. Is about 1k plus if i recall correctly back then. Now i dont know.

You will feel slightly better respond as your turbo now can spool faster due to better breathing downpipe. WHP and WNM will increase slightly....about 4whp and 13wnm (in my case back then, different car may produce different results).....But u can definitely feel the difference....Much more than u feel with an intake or drop-in filter.....

HAPPY MODDING

Great. It there will be more gains from having the catless downpipe.

Good luck.......