When straightening handlebars, the idea is not to put to any stress on
any other part of the bike and it is relatively easy to do, just takes some
practice and mechanical savvy!
(
that's where your mate comes in!)
The other suggestions are all good, just depends on the depth of your
wallet and, how much serious off-road work you do.
The good and bad point about handlebars that bend is, that they bend!!
That means stress relief - takes some of the shock out of the rest of the
impact to the bike.
The plus for new bars, well, they are shinny - new, and, yes, that is an easy
part of the motorcycle that can be upgraded = better look / more leverage
and less flex.
Also remember that you will have to do some drilling, there are some locating
dowls or pegs that will need to be added to the new handlebars.
Kind of prevents the handlebar controls from twisting around the bars.
Have fun choosing.
Mr mischief.