I have a friends S185 here at the house; it is too wet right now to do anything with it. They are 6000lb, 56hp turbo workin machines! The turbo though, kinda looks funny seeing how it is so tiny! It is amazaing the difference 56hp is to my little Kubota's 19hp.
I have rented and used the hi-flow trencher from our local Bobcat dealer/rental and used it on this machine. Talk about a trencher! It really cranked, even in our rocky soil.
Next time you rent, for fun, look up a CAT-247. It is a similar machine, except with tracks. I really like the tracked machine for wet conditions, or when low impact is needed(tracks spead the weight much better than the small wheels on the skid steers).