I have been running a drag style als for years (maybe gets used 10-20 a month for 2-3 sec each time)
I also ran a slight throttle kick and timing based ALS for a 2 open track/practice days on a tiny garrett t25 on a 2.4L engine, needless to say the set up really didn't need any AL. The engine did regain full boost instantly when coming back on the throttle. Only reason i stopped using it was the little t25 simply didn't need the AL as it already responded very well any time you were above 3k rpm.
Manifold and DP were custom built by Full Race (no cat) and showed no damage what so ever.
Turbo still has very little shaft play and there is no damage to the turbine wheel or housing. (inspected it all when i pulled it apart to test one of the EFR turbos)
Currently looking forward to a new secondary air injection set up on a 2.0l project over the next few months.