I think DP and another company I won't name because they charge a ridiculous amount for theirs make them that exit through the drivers side front bumper. (I don't know DPs price, but I hope it's nowhere near the £500+ of the other company)
No one makes them that exit behind the front wheels that I know of, you'll have to do that yourself.
They should save a fair bit of weight compare to a full system. Not totally sure how they sound on the Gtir , but I'd say my mongoose sounds comparable to the side exit I knocked up for my montego.