Mostly galling, Ti due to it's metals physical properties and Ferrari's very tight clearances the risk of friction welding is very high, the oil system needs to be at 100% at all times and oil viscosity, pressure and temperature are critical, the 360 even uses a coolant/oil heat exchanger to get the oil to temp quickly when cold.
If you're curious you can read up about it on this wiki page:
https://en.wikipedia.org/wiki/GallingAnother site I frequent that's a bit more technical but filled with great info talking about conrod materials:
http://www.eng-tips.com/viewthread.cfm?qid=90426Personally while I do like Ti rods and they have some great benefits, the downsides to sheer cost keep me from using them, shorter life span and the hassle/cost of tear down inspection etc... forget it. Now if I was racing or involved in racing then those downsides are factored against the edge one might get from the lighter rotating mass, then again it's not a one size fits all approach, endurance racing would make no sense for such high cost. 300M steel or better is fractional in cost and far better in it's elastic modulus.
Please don't take my msg as "never use Ti" for what I do and the engines I develop for Nick Forza there is also the issue of reliability and customer satisfaction, if the client wants a 'race engine' they can get one, I did develop a couple Ti conrod engines, one is being used for hill climb events in OZ. I just think that anyone building an engine should have at least some information on the choices they have beyond just 'this is the best' as there really is no such thing. it's all about compromise.