Corolla Help Required

[corolla abc]

I have a 1993 Toyota Corolla T3. A couple of years later I added the Turn by Turn Sat Nav System to it because at the time I could not afford the full Colour Screen version. My unit is the TNS 300 and uses the standard head unit and has the DVD system fitted under the passenger seat. I now wish to upgrade to the full colour sat nav version and need some help with the following points.

1 Will the colour sat nav head unit fit straight into the dash ir does the dash need modifying.

2 Can I buy just the new colour sat nav head unit and will it work with the current DVD system and disk. When I added the current sat nav the cost wash £1100 fitted (that’s all wires etc…) and now my local dealer is trying to tell me that the Colour head unit on it’s own is £2200. This seems wrong as the whole colour system a few years back was £1950 including DVD player and fitting. Does anyone have the part number of a full colour sat nav head unit for this my Corolla?

Hope you can help.