Is this an ethical redirect?

Using a script to redirect without black hat tricks

[Ride45]

We run a site with a large number of products that link out to another website. However, we decided to use a PHP script to do a redirect for all 25,000 products. We did so for 2 main reasons:

1. It makes it easier for us to run user stats, and track product popularity, rankings within our own website, etc..

2. We did not want to have 25,000 outbound links to another website that was not our own.

The script does involve any black hat tricks like making the user see one page and the search engine see another. It simply works like this:

View product on our site > Click Product Image. The link for the product is a to a php script which takes the product ID and redirects the user to a corresponding product ID page from our supplier.

We have not had any ranking problems yet and we have nearly every page (25,000) indexed by all major search engines for over a year..

However, I woke up in a cold sweat last night, worrying about this.. should I just go back to sleep or wake up and smell the coffee? Thanks