Car Radio Upgrades

Best suited to cars where a double din can not be installed easily, for example the Toyota aygo in the centre picture below. these can be supplied with hands-free Bluetooth and audio streaming or without 

Many modern cars now come with a double din aperture size radio, these can be replaced with a wide range of double din radios or with the right fascia adaptor a single din.
these can be supplied with or without Bluetooth

Mechless radios come without a CD or DVD drive, they work out cheaper and are becoming vastly popular with people now using more smartphone based apps for audio streaming.
these can be supplied in touch or non touch, double din or single din, with or without Bluetooth 

This category only applies to double din unit the difference is the screen full touch capability like the Porsche below or push button style with a simple 2 or 3 line display 

Apple carplay and android auto is no widely available in a wide range of new cars on the road, this technology gives you the ability to plug your phone in and have your messages read out to you, access navigation via your phone, and access your phone for contacts in a safe manor while driving.
this is also available in wireless by using WiFi built in to the head units this feature is limited to only a few models from pioneer.

Navigation units work out a bit more expensive than standard car play units, they come with a separate GPS aerial and use built in navigation software. most of the units now also have carplay built in.