02 wrx wagon Performance downpipe and midpipe advice

I am in the middle of doing a clutch job on my 02 wrx wagon and after just taking off the downpipe and the midpipe I noticed the down pipe is rusted through is one spot and they both have cats in them. If I buy a cat-less pipe will the check engine light come on?


I see there is one for $70 free shipping on ebay. Is looks like a combination down and midpipe.

http://www.ebay.com/itm/02-06-WRX-STI-Impreza-Stainless-Steel-SS-Down-Pipe-DP-Turbo-Downpipe-Exhaust-Kit-/140996266613?pt=Motors_Car_Truck_Parts_Accessories&hash=item20d4084a75&vxp=mtr

I guess no one has any comments or knowledge about this.