Becker Sat Nav replacement

Hi guys. Just got myself a 06 Freelander and (thanks to various threads on this forum) stopped the boot from filling with water
Now I'm turning my attention to the satnav/radio. The car came with 03 maps loaded, the latest available are 08 for £145 cheaper with a new tomtom!

Anyway I intend to fit a double din touch screen radio/nav system from ebay to replace the becker unit and coin tray. The question is, can I connect the ISO speaker outputs to the HK amp or should I splice in the RCA plugs? Third option is to bypass the amp completely.
All I want is to hear the radio and see the satnav, I'm not worried about sound quality (I've got all those landy squeaky to listen to).
Any helpful advice?

Your HK amp will need pre-amp feeds from your new HU. You can get a double Din trim to fit the HU. You'll probably need to make up the harnesses for the amp though.

Thanks for that. Don't like messing with original wiring (and hate coming across other folks mess). I've ordered the trim panel and converter leads.
I'll chop up the converter leads and patch in the rca (pre-amp line out) outputs to the speaker connections, I'll also patch the electric arial output into the remote power on for the amp. I want to avoid changing any LR wiring, that way it can go back to the becker unit any time.
I had a feeling I'd have to do it that way, always better to ask though.

Quick update on the new head unit. The becker satnav unit uses standard iso plugs and the Harmon Kardon amp takes the high level speaker outputs, so the whole thing is a straight swap in terms of wiring.
Needed an antenna adaptor and the Becker GPS antenna is a different plug, rather than mess about I insalled the supplied antenna behind the dash cup holders.