Hennessey has 2 packages.
The first one is the HPE850 and that is the one that costs around $20K on top of the price of a new ZL1. At that stage you are getting nothing more than a pulley, HF LTs, cam, ported heads, intake, install and tune.
The Exorcist package STARTS at $55K ON TOP OF the price of the ZL1. So it is a minimum $55K upgrade. Now that package comes with everything that every other shop will offer and do and install and tune for about half the price.
CSP - $26,175
https://www.cspracing.com/2017-camaro-zl1-package/
WX - $19,599
https://weaponxmotorsports.com/colle...o-lt4-packages
VR- No price listed but I'm willing to bet it's a gang cheaper than $55K
https://vengeanceracing.net/index.ph...superchargers/
Race Proven Motorsports - stage 4 is comparable to Hennessey 850 but is several thousand dollars cheaper. Stage 5 is comparable to Exorcist but includes a PC blower and meth kit and is over $20K cheaper.
https://raceprovenmotorsports.net/co...mance-packages
So it is absolutely true that you can get the same or better performance from shops with a much better reputation and that didn't screw people over in the past and for a significantly lower price.