compressed air turbo anti-lag system

Storing turbo pressure to provide a burst of air that spools the turbo up to speed faster from idle sounds like a good idea. The compressed air could come from an electric compressor, as in Volvo's system, or could be bled off the turbo system continuously and stored in a small tank for an extra burst during spool-up. This seems better than powering the turbo continuously by electric or belt drive (supercharging) because it's only for a few seconds that you need the power boost. 

This sytem was expesive ($20K) and "way too costly to actual implement"
 http://scrmgarage.com/anti-lag-vs-zero-lag/

electric compressor fills a storage tank - 
https://jalopnik.com/volvos-powerpulse-technology-aims-to-end-turbo-lag-fore-1745961554

There are many potential problems with the method, though
-have to disable the engine computer
-additional air makes the mixture lean, if added on the intake side
-may force exhaust gases back into the cylinder
https://www.homemadeturbo.com/forced-induction-7/compressed-air-anti-lag-turbo-spool-659/

-temperature-stress on the turbo
-manifold pressure and temperature stress
http://rallycars.com/technical-stuff/bang-bang-or-anti-lag-system/