Is a header a good upgrade?

[Type-Y]

Thinking about getting either the DC Sports header or Weapon R as my next upgrade. Read conflicting reviews on which is better. The DC gives more gains up top and Weapon R gives better gains lower in the range. The DC used the stock heat shield and the WR does not - not sure how important that is. My car is an automatic, with a Tein Street Advance Z suspension, a K&N drop in and Tanabe Medallion Touring axle back. I know most opinions seem to say that the axle back doesn't give any gains, but after 5 months of use I still feel like my car has more pep than stock. My wife noticed it too and actually commented on it without my prompting, which confirmed my impression.

The header seems like a good next step, but wondering how much actual difference I'll notice. Any input and advice is appreciated.