5000 is very high. The Multijet, even though a small free revving diesel, is not an old school Honda VTEC with a superlight flywheel. Even if FIAT set the redline at 5000/5600/xxxx, doesn't mean we have to take it there. Even if nothing breaks, wear and tear of parts is accelerated at a fast rate at high rpm's. I've touched 5000 and the engine said to me , "Ok bro, lets not do that often ok?". Keep it in the 2500-3500 band with occasional rips to 4000 and everything will be happy. But hey, that's just my opinion. Cheers.