Changing Software on Site

To change or not to change?

[boxerman]

We work on an ecommerce site and are trying to decide to update the cart system but wanted to see if we could get some feedback.

The site currently uses oscommerce but a change to x-cart is needed. The conversion part is not an issue but we are worried about search engine rankings.

Currently the site is listed in the top 5 for all of the keywords that are targetted. The site focuses on gifts so the holiday season accounts for most of the income for the site.

If moved to x-cart, all text, images and layout would remain the same. The thing that will change is the URL to the pages. All incoming links point to the index page and not item pages so the incoming links would not have to be updated.

My question is if we were to change to x-cart

Is there a way to forward traffic coming into the old cart to the new cart? The current store resides in a folder on the domain named catalog. i.e. www.widgets.com/catalog/

If the pages can be forwarded to the new cart, would there be any penealities?

How long would it take to get the new pages indexed? The site has a PR5 with PR4 category pages, PR3 item pages. Indexed are over 2,000 pages and it has about 700 backlinks that show up in google.

I am mainly just looking for suggestions and ideas to make this conversion as seamless as possile. Thanks in advance for any advice.