1. The rods and handles are replaced in the full upgrade to get the current tournament-level response...
-- most people like the new plastic handles, which don't sweat up and expand like the old wooden handles did.
-- Plastic handles are more uniform, don't chip/crack round dowel holes like old woodies, or disintegrate after a few swaps.
-- new rods are supposed to be better machined & last longer, but I've seen quite a few upgrades omit these pricier rods.
2. The newer lower-profile bearings are thinner on the inside, which counters the thicker bushings..
-- Kinda helps the 5-bar immensely in hitting a ball on the wall for a wall pass, without squeezing the bushing.
-- Really helps the 3-bar even more critically, allowing catches on the wall without squeezing the bushing.
3. Getting the newer tournament version balls give the correct roll, weight and feel too, of course.
-- playing without the sidestrips ALSO REALLY CHANGES THE FEEL & TIMING OF most quick bounce passes, or banks..
-- the balls no longer skip right before hitting the wall as when the sidestrips were there... roll and spin are also quite affected.
4. If you're looking to restore it as a coin-op to put in a bar or other rec venue...
-- Get the coin-op mech from Jim who runs this board.. and there are others, of course.
-- For a bar or play table only... replace the rods when they break.. shouldn't make that much difference.
-- If you're running or thinking of running competitive tourneys like a DYP, then do the upgrade minimum kit at least.