You will have the choice of Single Tier or Multi Tier, depending on your preferences
yes you can download them for evaluation purposes.
Just take note of your Informix Variables as you will probably need them for the Client machine, that is if you use Single Tier.
Single Tier, much like any other ODBC Driver available which is client side only requires the installation of the Informix (Database Specific) Client Networking installed.
So you will need to check you Setnet32 for this values
Multi Tier does not as it uses an installation on the database server.