I am looking at buying a 9660(now a 9670)sts. Just wondering if there are any particular problems with this model. I am running a 625 flex and 893 cornhead. I do wheat, corn and beans. Is the sts easier to repair than a walker machineIJ Also, how much more capacity over the 9500 that I was previously running with a 920 flex head. wheat 70 bu, beans 45bu, corn 150 bu averages.