But your friend is right, at pre 1993 AMG was an after market tuning firm much in the same way Brabus still is, and you took your car to them (or ordered through them) and ticked the boxes that you wanted, so a genuine AMG car might not necessarily have engine modifications, you could just specify cosmetic alterations. The 6.0 engines, particularly the quad cams have a reputations of being somewhat temperamental and high maintenance, and they actually aren't that much more powerful than a standard 560 (300bhp standard - 360bhp 6.0 quad cam).
Certainly collectors pieces though, the widebody never did it for me though, the standard AMG kit looked nicer.[/QUOTE]
The 6.0 Quad cam pumped out 380 bhp....the smaller 5.6 (360bhp) and the 5.0 Quad Cam (340bhp). Where these engines really excelled was in the mid range.....dropping down through the gears a 5.6 Hammer (W124) would cover ground faster than a Ferrari Testarossa, Porsche Turbo and a Countach. They also topped out at 186mph
In terms of running one day to day, they were not as temperamental as has been claimed...most of the poor running was down to poor maintenance, ie there were/are only very few people who know how to set them up, ie valve clearances, timing etc etc....if you get this wrong even by the slightest of margins they will run like a dog and will drive dreadfully.
What you tended to find is that the owners of the cars when they were second/third hand etc tried to get local garages to set them up...they would then fail to get them running 100%, so exasperated owners would sell them on again and somebody else would have a go and make things worse and so on and so on.
With the eldest of these quad cam engines being 22 years old, many of the original mechanics who worked for the AMG agents have moved on or retired and the knowledge has been lost and its all but impossible to find any technical data for these cars and AMG themselves are not interested as it was prior to the Mercedes takeover.
In terms of the heads which are the critical items on the engine, all parts can be obtained, ie valves, springs, seals etc etc.....the only item that will cripple you, is if you wreck a head casting, as you will not find a spare one. Thankfully they are very over engineered and its the least likely thing to fail.
Great engines and hugely powerful when they were used by Sauber in their Le Man cars in the mid to late 80's where they twin turbo'd them....800bhp!
And lastly, the sound of a quad cam is like no other Mercedes...they sound more like a small block Chevy Nascar
)....but it's all the SVA and import duty and the fact most of these are left hand drive that puts me off.
