First, to hmouta, I have seen an Art Series amp once on ebay as a 4 ch. I believe the model number was A404, and I think it was 50W x4 RMS.
96tourkid-I think it is generally agreed that the crossover included in the speaker package will give you tuning designed specifically for those speakers, which will sound better than using the amp's built-in crossover. I think the speakers you selected are a good choice as a package. Also, I would advise getting an amp with more power than the JBL P80.4. At 4 ohms, it generates 40W, and you probably want closer to the maximum RMS power handling for those speakers. I would say go for 60-80W RMS per channel. I mentioned brands in my previous post.