Phono boards update?

System, NAC 102 (recapped 11/2015) NAP 108, NACD 3.5, Rega Planar 3 RB300 tone arm and Rega Exact 2 cartridge, Spender S8e speakers.

Hi all. 

 After a bit of a point in the right direction please. My NAC 102 has NA 522/4 phono boards fitted, which I use for my TT, the boards are stamped 99, which I assume is the year they where manufactured? My question is, would I gain much from replacing the phono boards for new ones, as the ones fitted are getting old now, or would I be better off looking at a separate phono stage instead, and what sort of level phono stage would be required to be at least as good as the naim phono boards, or preferably, a bit better?

Thanks. ��