This is from 18turbo.com, the registry of the quickest 1.8Ts and I included the software brand the owner lists using on the run;
This is just the facts, I am not sayin anything, draw your own conclusions...
heres the link btw;
http://www.18turbo.com/enter.html
11 SECOND CARS
11.851 @ 118.4 Mph - Pat Brown's 2001 GTI 1.8T - REVO
11.871 @ 117.3 Mph - APTunings 2002 GTi 1.8T - APR
12 SECOND CARS -
12.200 @ 117.0 Mph - Billy Tylaska's 2000 Golf 1.8T - APR
12.230 @ 113.9 Mph - Ric Fish's 2001 GTi 1.8T -APR
12.393 @ 112.9 Mph - Kevin Moore's 2001 GTI 1.8T - REVO
12.418 @ 117.3 Mph - Troy Casteel's 2001 Jetta 1.8T - ATP
12.512 @ 118.3 Mph - Steve Soeder's 2002 GTi 1.8T - REVO
12.584 @ 109.9 Mph - Sam's 2001 Jetta 1.8t - APR
12.609 @ 112.4 Mph - Nick's 2000 GTi 1.8T - APR
12.790 @ 113.3 Mph - Steve's 2002 GTi 1.8T - BCS
12.830 @ 109.0 Mph - Andrew's 2000 New Beetle 1.8T -GIAC
12.911 @ 110.33 Mph - Sam's 01 Jetta 1.8t - APR
12.961 @ 109.3 Mph - Tom Vortsman's 2001 GTi 1.8T - Upsolute
12.997 @ 104.0 Mph - Jonathan R's 2k Automatic Jetta 1.8T -GIAC
13 SECOND CARS
13.079 @ 109.4 mph - Tyrolkid's 2000 GTi 1.8T -GIAC
13.113 @ 109.14 mph - Rich Righetti's 2002 GTI 337 -APR
13.180 @ 107.4 mph - Stephen 2003 GTI 1.8T -REVO
13.205 @ 111.0 mph - Matt McClosky 2001 GTI GLX **VR6 - N/A
13.216 @ 108.5 mph - Sam's 3,145 lb 2001 Jetta 1.8T -APR
13.228 @ 103.43 mph - Adam Dismukes's 2003 GTI 1.8t -GIAC
13.230 @ 113.3 mph - Shaun Ledgerwood's 2001 GTi 1.8T -GIAC
13.253 @ 103.6 mph - Louie Lozano's 2002 GTi 1.8T Upsolute
13.255 @ 103.9 mph - Pat Brown's 2001 GTi 1.8T -GIAC
13.440 @ 105.0 mph - Darren's 2000 New Beetle 1.8T - APR
13.499 @ 101.7 mph - Drew Hile's 2001 GTi 1.8T -APR
I didnt list all the 13s, it was APR next, then GIAC, then Neuspeed, 13.5 was a good breaking point.