Just to let you know, TomTom 6 is for S60v3 devices only and will not run on S60v2 phones like then N70. It will run on the N80 as that is a S60v3 phone so if you need TomTom 6 I suggest you get yourself an N80 instead of an N70.
I have used TomTom 5 above though with no problems on my N70.
Hope this helps.
:Cheers: