It's also the extra heat to deal with, the most effective ALS set ups have a lot of airflow, more ignition retard and less fuel, the byproduct being lots of extra heat that will damage valves, turbos etc. If your seeing lots of positive boost pressure off throttle the the setup is Probbaly to aggressive, aiming for 0-1psi is a good range and will give nearly zero turbo lag when you get back on throttle.
The best way to set it up is with a EGT and aiming for temps no higher than around 800deg C, temp is reduced by reducing airflow (ie throttle opening), reducing retard, increasing fuel and increasing ignition cut.
I aim to replace turbos each season, so around every 600-800km of competitive use. That's using a ViPEC ecu, with a solenoid that opens the throttle to 10% when the anti lag is armed. I'd have to check the map to give you an idea of the amount of retard, ignition cut etc I use.
If you want the it setup so that you can use antilag sometimes you will need some form of solenoid to open the throttle, otherwise you will need to use rotational idle, which is NOT practicle for daily use.
