The GT Line S would be an amazing car, I’ve sat in one and it eclipses the GT Line and that stereo upgrade is much better than a Bose one. That car below £5,000 would be tempting, below £4K would be awesome.
We can live in hope. GT Line S has uses Meridian 14-speaker Sound System compared to Bose 8 speaker system in the i6 Ultimate. Bose for example is famous for emphasizing the mid-range, so will depend on ones ears which system is best. However many in car premium sound systems are licensed out to third party manufacturers.
Most OEM manufacturers still use relatively cheap speakers and still run on the theory that more speakers = better sound (it really doesn’t). What I look for is the ability to tweak the sound – the ZS has a 5 band equaliser and allows you to set the volumes to each corner so you can focus the sound to come from the front, mostly the front or all around. For best sound in the front seats you want the most of the sound from infront of you (all except sub bass is ideal). The ZS requires a certain level of rear sound as the midbases are much stronger behind and add some depth that the fronts simply can’t. So a premium sound system with a decent, programmable equaliser and I can get the best possible sound, usually the premium sound might add some deadening behind the speakers, improving their sound for little extra cost.
I'm Autistic, if I say something you find offensive, please let me know, I can guarantee it was unintentional.
I'll try to give my honest opinion but am always open to learning.
Mark