The cost of PPGs 1-4 Helical (stock 5th gear) is $4,000, Mfactory front LSD $650, Clutchmaster Stage 3 clutch $750, Act StreetLite Flywheel (13.9Lbs) $250, Transmission Rebuild $500, and un-install/install of tranny $350. This totals $6500, and is my list that I will be upgrading to in early spring next year. You can probably skip some parts on here to drop the price, or maybe some different ones. But from what I have been researching this would be a solid setup.
As far as the 6SPD goes, it depends on what version and what year you get to how expensive it is to both purchase and install. I had a long conversation with the guys who are doing my work about which way to go. I actually could have gotten a 6SPD for about the same price, but not every6SPD takes everything that some people say (like I was told when I was new and didnt know). But you being in Europe, what model do you have? And I have no clue what type of shops are like or capable of over there.
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX