I recently purchased the worker Caliburn kit and man was i impressed. Maybe I got a golden sample or maybe Worker is shipping the kit is a heavier spring, but my Caliburn was hitting ~260fps avg using AF half length pro darts over both my chronographs with the included spring. While i like the high velocity, the spring weight is heavier than Id like.
The 788 performed better than I expected. The spring weight is noticeably lighter than the stock spring, making the blaster much more enjoyable to shoot.
And over the chronographs I got velocities of ~235 fps, which is higher than i expected.
I haven't tested the performance with the spring cut down to 10", and i likely wont get around to it unless i buy another 788.
Overall, I am perfectly pleased with this product. 5 stars.