Hi Octanium
The GTi is usually the top of the range... (on newer golfs however, this is not the case... V6 4Motion and R32 are the range toppers)
On MK1 and MK2 Golfs, Lupo's and MK5 Polos (Designated 6N2) the GTi is the top of the range car.
For Polo's the only GTi to be sold in the UK was a 6N2 year 2000-2001 model (MK5) Polo. In Germany (not sure about the rest of europe) there was a 1998-1999 6N (MK4) Polo GTi which had the 1.6 16v 125Bhp engine.
The UK Specification 6N2 (MK5) Polo GTi has the 1.6 16v 125Bhp engine with variable inlet timing and "Drive by Wire" throttle. It also has the following which make it more or less unique in the Polo world...
AS STANDARD:
15" BBS Split-Rim Alloys
10mm Lower than standard
Mesh Grille
Xenon Gas Discharge Headlights
Deeper front bumper (fender)
Deeper side sills
Uprated Gas Shock Absorbers
Cable-Change Gearbox
VW Climatronic Climate Control (Automatic Air Conditioning)
Leather Gear Knob
Leather Stearing Wheel
Leather Handbrake
Sports Seats (Both Hight Adjustable)
Chrome Instrument Surrounds
VW Gamma Stereo with 6 Disc Changer and 6 Speakers
Alarm with Interior Protection
Front Fog Lights
Electric Windows
Remote Central Locking
Electric and Heated Wing Mirrors
Colour-Coded exterior parts (Mirrors, Rubbing Strips Etc...)
Leather Interior was an option.
The Polo GTi was a limited supply vehicle, therefore you do not see many of them on the roads... My dealer only sold 4 or 5 new.
The specs are 0-100km/h (0-62 Mph) = 8.9s
Top Speed 127Mph (I don't know what this is in Km/h)
Therefore...
The Polo GTi isn't just a badge
and no, you can't really make a normal Polo into a true GTi (although you can make them look fairly similar - see Tigor)
The price new for a Polo GTi was over £14000 UK Pounds (ie. over 216,365.88 ZAR South African Rand!)
I like mine!
Hope this is enough information for you... If you need any more, just ask!