The issue with reducing preload to prevent overboost on a stock port size is reduced response and high rpm blow out. Ideally you want the wastegate closed as long as possible to maximise the drive pressure on the turbine (for response) and then you need the port to flow enough in the midrange to prevent overboost, but still enough control (from a decent spring rate) to prevent the gate blowing open up top.
If you have any post or pre turbo aiflow mods and want to use your TS IWG you'll at minimum need to get the tune adjusted to suit and potentailly you will need the port job.
FWIW I really like they TS actuators. They need slightly different approach to set up and tune than a stock garett unit but IMHO the higher mass of the internals helps improve spool up and give a smoother curve (assuming mech conditions are correct to support this)