I do see what u mean.. best not to over run an engine thats not functioning correctly or over-power with straining it.. I purchased the car from GKS of ivybridge and now feeling i should of got it checked over before buying as first owning the ST170 i was told the brake disc's were renewed and heat shield.. but still had to have the lamba changed and a resistor to the heat and cool fan replaced, as it would only operate on 4 before now works with 1 2 3, but odd times rattles, feelings of concern that i could of purchased a car with faults that could of been ignored.