Dear,
Thanks for contacting us and apologize for the late response.
1. Yes, this unit will fit your car,plz place orders directly on our website.thanks for your order in advance.
https://www.seicane.com/android-for-lexus-is250-radio-gps-navigation-system-with-bluetooth-hd-touchscreen-carplay-support-swc-h2572
2. IT build-in radio, you need use ours.
3. Yes, your OEM CD player can still work perfectly.
4. If the plug of the camera video out cable of your original car is the same as ours camera video in,then it can support your factory backup camera.
Instant payments are very important; the earlier you pay, the sooner you will get the item.
Please feel free to contact us, we are always at your service.
Looking forward to your purchase.
Have a nice day.
By
Seicane