The USA is a key market for all Audi RS models.
The RS6 has been a huge success. Audi sold about 8,000 RS6s (all versions) worldwide of which the US took 1,000. That's a lot.
So, as you can imagine Audi is pretty keen to build on that success with the new RS4. It certainly expects to sell 1,000 new RS4s, but could sell twice that amount because the RS badge now has a much stronger and more universal image. The new RS4 is also substantially less expensive than the RS6.
The latest RS4 was designed from the outset to sell in the USA, so configuring it to local requirements will have already been done. in other words, this will not be a factor that delays its introduction stateside. May sounds way too late. I would be surpised if the RS4 didn't arrive by March. The only thing that would delay US production is unexpectedly high European demand. Audi may be saying May in case this happens.
Something else really important to say. Audi presently sells about 80,000 cars in the USA which is only a fraction more than it sells in the UK. This is terrible considering how good both product and brand are. Audi realises this. And, as it has made abundantly clear through recent press releases, we should expect Audi to substantially ramp up its marketing efforts. More impoortant it will align itself with what the market demands. At the moment, hi-performance wagons appear to be a European phenomenon not a US one. If you tell your dealer you want an Avant version of the RS4 and there is enough interest, it will surely be imported.
I would say that 500 orders would be the miniumum to make federalisation worthwhile and perhaps we could submit a petition of potential US Avant purchasers to Audi USA to make this happen. Such a petition would require refundable dollar deposits to be submitted.
We as users of this site, have power to make this happen - it's the beauty of the internet.