Installing catless 1999 header on my 02 vfr. Tuning change required?

Hey guys new here. Just got my first vfr about a month ago. Love the bike so far. When I got it I gutted the stock cat and mufflers and put a power commander on it. Got it running amazing. Well I came across a 1999 catless header for cheap so I bought it. I was told it will give a bit more power mostly because of the larger head pipes. Like I said I have my bike tuned about perfect for the stock header with gutted cat so do you think I will have to tweak the tune after installing the 99 larger header? Just looking for opinions. thanks