Intel 9 series chipset does not have official support for XP. It may work actually but it's untested. Also intel does not provide AHCI drivers for XP for this motherboard, neither AsRock. Either use generic ones made by Fernando or switch to IDE mode (not too good for SSD disks). Consider older board with intel serie 8. Also pay attention that only some motherboard have overclocking ability with H87, H97.
Windows XP does not support SSD disk correctly so it may have significant signs of usage after short time. Since PC for mame does not require fast HDD You might consider standard HDD. If You make selection of games everything will fit even on 160 Gb (unless You are planning use Hyperspin with movies). Performance under XP x32 or x64 is lower than on 7 x64 and it's noticable in mame.
4 Gb of RAM is more than enough for MAME. 16 Gb is absurd. Besides even G.Skill is great brand (I have 16 Gb G.Skill in my main PC) I prefer cheaper RAM for mame PC. If it's only for mame and other emulators pick value ones.
PSU is fine. Similiar one is still in PC of my wife but about year ago Corsair had many problems with faulty PSUs.
Processor is the best choice but must be overclocked. The best ratio would be from 3,8 GHz to 4,3 GHz.
Video card is ok but it's overpriced, it can found cheaper.