E-grips are nice, go with that. the low-pressure kit, works best with HPA/Nitro. It is an expensive set-up, but over time will pay for itself. Since your gun will use a lower system pressure that means less recoil, more control, better accuaracy, and a sound reduction. You really should use an RVA or spring kit with this set-up to further increase your efficiency. If set-up correctly, you will very likely be able to shoot almost a full case of paint out of a 68ci 5000psi tank. The marker has much less recoil and drop off has been reduced so long strings of paint stay on target.
Here's my recommended set-up, a low-pressure kit, a 68/4500 nitro tank, a good secondary regulator (I like palmers), a low pressure gauge (the kit does not have one) so you can read the input pressure to the valve assembly.
Let us know how it works out. Good luck with your purchase.