Just recieved my dougs d450 headers Wowwww

Say what do you guys think of the small 2.5 collector on the dougs ?
I plan on 2.5 head pipes > dynomax ultraflo > 2.25 tails .. would there be any gain by loosing the 2.5 collector and adding a 3" instead ??
probally no gain............. because i'm running with 2.5 head pipes anyway.
that 2.5 collector just seems pretty wimpy to me. but if no gain with 3" collector ...... it does matter anyway. just wondering