I owned a '00 Passat 1.8T for about 2 1/2 years. I loved the car, specifically the way in handled, the performance and the versatility. It was totalled in an accident about 3 months ago...RIP.
I bought an Acura CL-S instead of another Passat. The reason was because of reliability issues. It is a well documented fact that the last generation of VW's had some serious engineering and quality control issues such as oil sludging, coil packs, control arms, panel fitment, window frames, etc.
It took them a very long time to develop the new cars. The B5 Passat was first made in '98; it took until the '06 model year for the B6 to come out. 8 years is an eternity in the car business to come out with a replacement model. I would be willing to bet that the quality and reliability of the new models is much better than that of the last generation. VW is embarrassed at how bad their reputation was besmirched because of the quality issues. Of course, new data is not readily available yet as to the reliability of the new gen. Also consider the warranty; if it's still 4 years/50,000 miles then you are set for a long time.
Another big thing to consider is the VW culture. I too was a member of VW Vortex and PassatWorld. There was a wealth of information available including DIY's with pix on anything I ever wanted to do to my car. Plus, the attitude of the members was fantastic. It reminds me a lot of this forum as a matter of fact. Most people are willing to help out and the scumbags get tossed. I am now a member of Acurazine and the difference is shocking to me; to say it's not the same would be a gross understatement. I don't know anything about the Mitsubishi culture, if indeed there even is one. There is much pride that comes from being a VW owner and from my point of view the new GTI is the jewel of the lot. It doesn't get the most publicity by mistake. Since you're a member of this forum I think you would also enjoy being a VW owner.
That's my $.02; good luck with your decision but keep us posted. I would like to see what kind of a system you put in and how it turns out.