Nice tractor! Yup, mine idles at 1,000 rpm as well. I use mine for tree work in the woods and have been very impressed with the R4 tires. My previously owned Mahindra 4540 had R1's. They got excellent traction in the woods, but they also churned the ground up and left ruts everywhere I went. Also, their load rating was not very good. My loaded wood box on the 3 pt. would cause the sidewalls to bow, allowing the tractor to sway side to side. Not very fun while working on a slope.
My 5155 has R4 tires and I really like them compared to the R1's. I've noticed no loss of traction in the woods compared to the R1's. Instead of churning up the ground and leaving ruts, they compact the soil and make sturdier tote roads. I really like that about them. They also carry my wood box without bowing whatsoever, since their load rating is much higher than the R1's. As Andy stated, they're more puncture resistant, too.
Also, my rear tires are loaded with RimGuard (beet juice).