Bear in mind that depending on the extra pipework used a FMIC can increase the boosts bath and diameter etc can adversely affect the power, creating more lag.
I run two side mounts still, never had any problem with heat soak, but then the bigger the turbo the less work it has to do to get the same kinda power as smaller turbos so less heat.
My car was all done when I bought it, was lucky enough to buy a fast and nicely sorted one