No need at all to balance the crank, they are very good as std, whilst things are apart why not lighten your flywheel, I got my std 2wd one down from 8.9KG, to 6.6KG for £40, which will show a big difference, I then further lightened it to either 5.6 or 5.8KG with some slotting, but this cost around £70 extra, so nowhere near as cost effective as the initial lighten.
It was also balanced at the same time of course.
tabetha