text: $12k for 80 more hp is a huge waste of money. First, that is an improvment in hp of about 13% over stock which you probably wouldn't be able to actually feel and which you could probably gte by doing some simple bolt on modifications like intake, exhaust, new spark plugs, a chip, etc. which would cost far less than $12K.\nIf you want to retain your warranty and the driveability/comfort you desire (especially if you bought an SL65) then you wouldn't necessarily do anything to modify it.\nAlso, a mustang would have to be dramatically modified to get into the 8s in 1/4 and I doubt that any of those mustangs in the 8s are actually street legal. \nIf you thought that the SL65 would be the fastest car ever than you may be a little confused. If you want an 8 second car then you should sell the SL and get a mustang and modify it. I would guarantee that it won't have the comfort, driveability and sophistication of the SL. Personally, as a daily driver I would much rather have the SL than the mustang.