Is this correct? I got it from GTTi club UK...
Engine...
Modify in this order...
1. Air filter - even a replacement panel filter for the airbox is better than the standard item. BHP over 100
2. Exhaust - mandrel bent. BHP now 110
3. Turbo to downpipe extractor - if your budget allows. BHP now about 115-120
4. Fit a boost gauge and raise boost to safety limit of around 12.5 psi. BHP 130
5. Add a fuel cut defender, raise boost to 14.7 psi. BHP 140-150
6. Fit a Hybrid turbo. 150 BHP
7. New ECU and uprated MAP sensor. 150+ BHP
8. Copper head gasket / ported head. Boost raised to 20 psi. Better fuel pump. 170 BHP
8. Larger throttle body. 185 BHP
9. Lots more ££££'s, bigger fuel injectors and more boost!
10. Congratulations...go join the 200+ BHP club!
Source:
http://members.aol.com/Lverrecchia/public_html/mods2.html