Bada Bing

We're thinking about getting a basic A4 2.0T FWD CVT Premium for my wife now and then replacing my 2007 335i with a Premium Plus S4 in late June when my BMW lease is up. The lease payments for an S4 based on current lease terms are way more than what I'm paying for my Bimmer right now (like $250/month more!), so I'm trying to see how much it would help to close the gap a bit if I qualify for loyalty money when leasing the second Audi. If the S4 is still too much, I'll go with a 6MT A4 2.0T quattro.

Thanks!