Date registered: Apr 2010
Vehicle: '89 560SEC, '90 560SEL
Location: God's country, near Billings MT
Mentioned: 1 Post(s)
Quoted: 97 Post(s)
Yeah, avoid the Febi tensioner. Febi isn't universally junk (I have a "Febi" oil pump in my SEC that's just a re-boxed OE pump, for instance), but it's a brand that has at least as many misses as hits, quality-wise. Caveat emptor. Not sure what the failure rate is, but I've heard enough bad reports that I'd leave the original tensioner in before I'd use the Febi one.
You should be able to do the whole job for $500-600 in parts. I priced it out a couple months back, but can't remember the exact number. Most people don't replace the sprockets, and it's not necessary unless you've got really high mileage and/or they show a lot of wear. It's the tensioner and plastic guide rails that cause failures.
'89 560SEC, 234K, pearl white with palomino interior - Liesl
'90 560SEL, 192K, champagne with mushroom interior - Ingrid
'97 Ford F250, 189K, diesel, blue, 4x4, manual
'64 Ford Fairlane with approximately 240K