Hello, unfortunately there is not much aftermarket support for the 1G probes. are you looking at upgrading turbo? intercooler? cold air intake. there are chips avaliable for the ECU goto MX6.com - powered by vBulletin or XOOPS Site - News to find some info on the chips.
First thing I would recomend is a Manual Boost controller and increase the boost until you hit fuel cut, then back it down about 1 - 2 psi. If you decide to get an aftermarket chip you will be able to run 16 PSI safely on the stock turbo, I would also recomend getting a 2.5 or 3" exhaust done (Mandrel Bend), then get your intercooler piping built 2 - 2.5". most of the performance mods will have to be custom made, there is 1 company that makes an exhaust for these cars, just visit the web pages i mentioned above and you will find lots of info using the search button, also visit Performance Probe