text: is it pointless to tune my sl65 to 680hp? i recently bought a sl65 with 604hp and many people are telling me to renntech it to 680 for about 12k. however, many people i know who own ferraris or m6s who dont do anything to tune their car. alot of people simply buy the fastest version of that particular model and dont do anything after market to it. i'm not going to take the car to the drag every day, but i see mustangs doing 8s 1/4s. whats the point of the "604hp version" of the sl if a mustang can easily beat you. $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. if 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. also, 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.  if 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.