[Holyterror]

Titanium valves are definitely worth it if you can get them. Two reasons:
[list=1][*]Performance - I have seen great results in engines with Ti valves. In highly tuned examples, anywhere from 10-25 horsepower was gained. Some of these valves were slightly different from the ones they replaced (other than being titanium), but regardless, peak horsepower increased. But it doesn't stop there. In my opinion, the best part was how the power curve was affected. Rather than dropping off sharply 200-500 RPM after the peak, the Ti valves allowed the engine to keep producing significant power for almost 2000 RPM past the peak.
[*]Reliability - The reduced burden on the valvetrain will almost certainly mean longer life for the top end. Your valves springs will thank you especially. Even if you go for the hydraulic cam, you may find that the lighter valves let you go a bit past redline. I wouldn't neccesarily advise that, however. I think lifter life increases as well (at least with roller cams). In short, the Ti valves give you some peace of mind with a modified engine.[/list=1]

BTW, I think a turbo Fiero would be awesome. Don't hesitate to ask for advice on turbos, and let us know how it turns out.