The answer to your question is likely highly dependent upon the type of "competition" you are in, your ultimate goals, and your budget.
PRS/NRL22? benchrest? local club? nationally sanctioned? ???
A couple of thoughts:
1) If you change a barrel many organizations will no longer let you compete in "Factory" classes. You may then have to compete head to head against full custom rifles.
2) There is literally no way to make a CZ457 competitive in Unlimited BR competition.
3) The CZ action is not strong and is not the best candidate for a heavy contour barrel.
4) If you choose to replace your barrel, which MAY or MAY NOT improve precision, the best chance of maximizing precision is to go with a top tier barrelmaker. If a prefit, NOT WL or IBI or EABCO or PetesP!. Better yet, a gunsmith installed SS true match-grade barrel from Shilen, Muller, Bartlien etc..
5) You may (very probably) be able to dramatically improve the precision of your factory barrel/rifle with the use of higher quality ammo, especially a type and lot that has been tested to work in YOUR rifle.
6) While Vudoo's are great rifles, they are very expensive relative to a rebarreling, other improvements and modifications, and many other rimfire rifles. Vudoo's are also barrel dependent and you should order one with a top tier barrel (i.e. Bartlien).
7) The plastic pillar bedding of the 457VMTR is not well done as the pillar material compresses and the 457's precision is very finicky with respect to action screw torque. Factory class allowable modifications such as proper pillar/epoxy bedding, trigger modification or replacement and re-crowning of your factory barrel may provide improved precision at a fraction of the cost of a Vudoo, and would be advised even if you choose to upgrade the barrel.
Apologies if you are already aware of this stuff.
