I know there is article about lowering the torsion bar on GTT but without pictures it is very hard to do it for the first time. Since I'm not allowed to post it under "ARTICLES" section will do it here.
1. Required tool: Bolt M10 (approx 10cm long - gearbox one will do the job), nut for M10, washer, spacer (you can use 32mm snap-on piece) and key 16/17
http://img23.imageshack.us/img23/542...ar01op9.th.jpg
2. Other necessary tool: hand lift and two support brackets
http://img27.imageshack.us/img27/671...ar02as5.th.jpg
3. Take of the wheels an fit brackets under the rear axle
http://img27.imageshack.us/img27/760...ar03jh0.th.jpg
4. Best place for fitting the bracket is just under the torsion bar opening
http://img444.imageshack.us/img444/9...ar04pj0.th.jpg
5. You need to take the protecting cap off
http://img10.imageshack.us/img10/765...ar05jn2.th.jpg
6.View from the rear
http://img518.imageshack.us/img518/9...ar06oa6.th.jpg
7. Unscrew lower shock bolt (key 18)
http://img152.imageshack.us/img152/6...ar07op4.th.jpg
8. Make sure that you completely remove the bolt
http://img152.imageshack.us/img152/7...ar08ql1.th.jpg
9. You need to take of rear bodykit arches: take a look where the holes in quarterpanel are if you are not sure how to remove them
http://img201.imageshack.us/img201/1...ar09ul2.th.jpg
10. Measure distance from the chassis to the central hub
http://img183.imageshack.us/img183/4...ar10ld7.th.jpg
11. Place the "specialized" tool on the torsion bar opening (it hoes in this order: bolt, nut, washer, 32mm snap on)
http://img25.imageshack.us/img25/958...ar11vu3.th.jpg
12. Screw the bolt into torsion bar
http://img21.imageshack.us/img21/680...ar12pt6.th.jpg
13. Place the key on the nut and move it in the direction like you are unscrewing it - toward the torsion bar
http://img407.imageshack.us/img407/4...ar13kf5.th.jpg
14. Torsion bar is pulled out - you can pull it completly by the hand now
http://img407.imageshack.us/img407/9...ar14ui1.th.jpg
15. Make sure that you remove plastic pieces that are holding rear brake cables
http://img179.imageshack.us/img179/6...ar15yo2.th.jpg
16. Torsion bar - make sure that you give good clean with metal brush and put some grease on the splines
http://img179.imageshack.us/img179/8...ar16ny7.th.jpg
17. Place the hand lift under the rear axle and lift it depending how much you want to lower the car (if you want to lower it for 20mm lift the axle for 20mm and so on...)
http://img19.imageshack.us/img19/763...ar17zk6.th.jpg
18. Insert the torsion bar back into the hole and rotate it until you can push it in completely (you can give it few bangs with the hammer at the end)
http://img515.imageshack.us/img515/7...ar18md3.th.jpg
19. If you are going lower than 50mm you will need to pull aux tank a bit inside so you can return the shock bolt in
http://img6.imageshack.us/img6/7306/...ar19ap7.th.jpg
20. Final result (car lowered 50mm)
http://img22.imageshack.us/img22/722...ar20wm2.th.jpg
