Informix and ASP

We have our legacy system running on Informix SE (can't remember which ver). A yr. back we started to do web development but we were concerned about security so implemented SQL Server 7 solution which transfered data from the SE to the SQL Server on a nightly basis then our web (ASP) apps run off that. Security is no longer our concern and the transfers occasionally fail (not to mention that that solution doesn't offer live data) so we now want to get the info straight from our SE database. Our apps were written using a single connection variable so theoritically, to change data providers, we only need to change that variable (a DNS-less connection). I know some of my queries may need modification (eg. SQL Server - fieldname LIKE "%", SE - fieldname MATCHES "*"). But I'm more interested in knowing which SE data provider to choose and how much it will affect my present apps as well as any other caveats. I'll greatly appreciate any advice. Thanks Austin