Hey Bob... IMO... leave the urethane bushings to the racers & those that don't mind the harshness & squeeking!
The factory stock rubber bushings do not squeek & you will have a smoother ride! Also, for the adventures most of us undertake, the stock ones will last a long time!!!
Even after 48 years of abuse, Xena's are still fairly decent, but I am going to replace them in the near future!

Have FUN FUN FUN!!!
Michael Cates - ManxManiac - the 'Maniac
Ventura, CA
Manx Club Member #958 
www.dualsportbuggies.com