The titanium exhaust is well worth $1600, it's just a matter of whether you want to spend it. Pretty much any 3" mandrel exhaust with a good downpipe flange design and a free-flow muffler is going to make a lot of power. But titanium does weigh about 75% less. Were you talking to Alex at Bozz? He won't give you bad advice when it comes to tuning, but he is a super JDM whore.
Oil catch cans are there to keep oil vapors from flowing through your intake, compressor, and intercooler. They are worth having.
Finally, no, a turbo timer is not necessary on a stock turbo.