Timing belt done at 151,000kms. I helped do one at about 180,000kms, but it was a 2000 model. Specified interval is 144,000kms, but there is some leeway built into that I think. Better safe than sorry though, as the ST11 engine is an inteference one (ie valves hit pistons if the belt breaks)
Performance wise, I don't think it goes any worse than when I got it (70,000kms) and probbaly not much different to new. A bit of a testament to the overengineering in there. ST13 looks to be the same, as there are ones around with well over 100,000 miles.