I have tried standard STI 170mm mags with stock internals, with 9mm follower/space, 9mm TTI follower/spring with Hardy spacer and SPS 170mm mags with stock internals.
The SPS ran strait out off the box and when it starts to have feed issues, then change the spring or pull it back to specs. Sometimes it can go salt shaker on you if you load it with 29 rounds and slams it very hard into the gun. (Happened to me twice at a IPSC level 3 and 4 match)
STI mags needed some feed lip tuning and after that, it didn't make any difference what internals I used in it.