I'd not get them. It's one thing if your a newbie and haven't figured out gear mesh, but really, my spurs last me an entire season unless something stupid happens, like with yours.
Engine gets loose, CB bearings go out, bent 2 speed shaft... all things that make spurs go bad. These are also things that wouldn't do any favors to the TiNi ones either. They may live through it, but I'd have to imagine they would show signs of wear.
Considering the cost of plastic, I'd stick with plastic. It's nice to have a weak link somewhere that's easy and cheap to fix. They are also lighter, so you don't have much lag getting the gears up to speed.