I mean I've had titanium exhausts on my e46 m3, my evos and my subarus. Yes titanium is more expensive but the weight savings are significant, especially for a car like this where less weight makes a real difference.
Before purchasing my ST I had a 2013 Subaru BRZ. The company Tomei released 3 versions of a titanium cutback for the BRZ/FRS that was less then $1000. Here are some pictures. I know it can be done for a reasonable price and I was just looking to explore options.