I've seen a couple of posts like the one I've copied below. Haven't tried it, but I will when the time comes.
Join Date: Jun 2011
Location: United Kingdom
147 2.0 l Lusso
Originally Posted by David C
Did you mean "bar" instead of "bed"?
To get the bar out you need to drop the front subframe, so it is not a quick job!
It is possible to replace the bushes with aftermarket parts, but it is quicker and better to replace the whole bar.
When I did this job on my 156 s few years ago, I removed the main subframe bolts one at a time, and replaced some (4 ?)of them with lengths of threaded studding and nuts. I then ran the nuts down the studs to lower the subframe enough to feed the ARB out one side. With the new one fitted, I could then just wind the subframe back up into position without any alignment problems. Whole job took about 3 1/2 hours and saved me about £400 on main dealer quote.