I also sent my older CX4 Storm to SP for all the hard internal mods shown in the vid-they returned a rifle that can best be described as now 'clockwork' in feel and performance-worth every penny of the roughly $1000.00 bucks we paid and well worth the rather long wait before SP called and told us to ship in the gun-well over a year as I recall.
What I don't understand is why anyone would shorten a barrel of a pcc-the stock 16" (CX4) barrel is absolutely ideal for both close quarters and for reaching out to distances that most here would dispute as being within the capability of the rifle additionally of course the length allows for any version of 9mm to fully develop all the power available.
Another 'benefit' of having the modded Storm is that there is no other rifle I am even remotely interested in purchasing as we are certain it would disappoint in comparison-so rather than being an hideously expensive version of the CX4 Storm in the end the rifle turned out to be a bargain.
The reliability and simplicity of a blow back pcc cannot be overstated or for that matter, underappreciated.
View: https://www.youtube.com/watch?v=0DWyJVpzkOk
An excellent presentation I thought.