should be less hold sensitive so long as the gun is not powering up a lot.
These tune kits are designed to have tighter fitting guides etc to help ensure any recoil is straight back. Also no twang or vibrations.I know the Vortek Pg2 In my m48 is much less hold sensitive than stock. Also due to the nature of the spring selection etc lock time of often decreased and this translates into increased accuracy so long as all the rest of the guns parts are in line (crown breech seal, no burs that can damage a pellet).
You might need to play with the hold of your gun as it will be a totally different animal with a tune kit, it is subjective however what you think of it and how much difference you see.
If you want less hold sensitive you might want to look into a soft tune... do all the right things with the guide,spring selection and seal and then using a less powerful spring and dropping the power some can turn some guns into amazingly accurate machines!
You might want to Talk to Vortek/Tom Gore and ask your questions vihttp://vortekproducts.com/ourstore/index.php?route=information/contact
TGore is very good about getting back to people and answering there questions.