GA16 works but I still think they remain unsupported by Nistune. This may have changed however but, even if it were, it offers nothing over the K11 ECCS unit.
SR20 variant has been used before but requires re-wiring and additional hardware to function. You're still limited to Nistune unless you're trying to utilise a plug-n-play ECU replacement, such as an Apexi Power-FC, (which was done once).
Unless you manage to pick something up for easy money, it's a lot of work for minimal gain.