So, in the sakes of fairness, whilst the GTI loses out on basic price (and perhaps quality), it does counter with some extra equipment that is optional on the BMW
1. Keyless entry - standard (£500 option on BMW)
2. 3 Zone climate control - standard (only 2 zone on the BMW)
3. Safety pack - standard (Travel assist, adaptive cruise, side assist, lane assist, emergency assist (£1000 option on BMW)
4. IQ matrix LED Headlights - standard - (BMW IQ Headlights are £500 option)
5. Heated Steering Wheel - Standard (£150 option on BMW) - anyone else find it weird you get a heated steering wheel but not seats ?
6. Load though system and lumbar support (each are a £150 option with BMW)
7. Digital dash on GTI Standard (Only contained in BMW Live cockpit professional for £1000, and arguably a worse implementation)
8. Wireless phone charging (£350 option on BMW)
9. Manual gearbox available on GTI (for £1,500 less than the DSG) - no manual option on BMW
BMW Counter with
1. More power 265ps vs 245ps
2. More Torque 400 Nm vs 375Nm
3. Mechanical LSD - Electronic only on GTI
4. 4 pot 360mm Front brakes (312mm single pot on GTI)
5. 2 pot 330mm rear brakes (300mm single pot on GTI)
6. Heated seats standard on BMW (£270 winter pack option on GTI)
7. Extendable seat squab (not available on GTI)
So if you add the "missing" equipment above to the BMW it's an addition £3,800 (£500+£1000+£500+£150+£300+£1000+£350), it would bring the 128Ti basic price to £37,120 vs £34,960 for the GTI (DSG), plus the £270 you would have to add for Winter pack on the GTI make it actually actually £35,230. That's always assuming of course the "missing" equipment matters to you at all.
Also, don't' forget the BMW will always have more power, more torque, the LSD and much more powerful and blingy brakes as standard, and BMW has some much nicer colours to choose from as well - mmm.. Misano blue....