I had my Jap A5 32" barrel reamed to IMP/MOD. The 32" just swings so nice on waterfowl. Still shoots great patterns of steel. The cost of cutting and reaming and threading chokes (when done right) is not cheap. Don't forget that when that barrel is cut the vent rib will be without the solid portion on the last 3". That's what makes the gun look finished, without it, it will look cut. Just my two cents.
Darryl