CSV information merge

Hi,

We are currently running SD 7.6.0 build 7604.

I have about ~100 machines that are in Service Desk Asset Register, that we have had to wait an exceedingly long time to get Lease information from our Lease provider.

As such I need to update the following fields;

Resource Info\Vendor Name
Resource Info\Acquisition Date
Resource Info\Expiry Date
Resource Info\Warranty Expiry Date

Asset State\Asset is leased (Flag)
Asset State\From
Asset State\To

Plus an additional asset detail field we have created;
Additional Asset details\Contract

I have all the information in an Excel Spreadsheet - specifically a serial number - which matches the asset records in Service Desk.

Can you let me know the recommended method for performing this update;

* should I export all the required serial numbers, manually update the fields I need, then import the lot
* or can I just list only the fields I need to overwrite, and SD will index the serial number, then update the above fields?

Thanks,

Geoff