The factory vehicles come with an electronically controlled internal wastegate.
External wastegate upgrade requires you to change the internal manifold runner design as well.
Core advantages are: Control boost better. Less cylinder pressure. Much lower EGT. Safer and more reliable.
Hence you can make a ton of power with the external wastegate upgrade & proper ECU tuning.
For example, stock 274BHP puts down about ~210-230WHP on dynojet.
LAP3 has put down anywhere from 340-370WHP with their Wastegate Upgrade & ECU Tuning.
You simply can't make that kind of power on a stock wastegate, where the limit is around a bit over 300WHP range.
Link to the post:
https://www.facebook.com/Lap3usa/posts/1671291329604811