Weld 2.5" Collector On Dc Header?

[GANGSTA]

I Need To Get The Jdm Dc Header Or The Other Header Brands That Has A 2.5" Collector.

Now.... Do I Really Need To Go And Buy Another Or Is It Just As Good If I Took It In To Get A 2.5" Rewelded On My Existing Header?

 

[GANGSTA]

i mean..... to just cut off the collector, and put on a wider one