Yes it will add more stress of course. But when you think the old Volvo AD41 which started off as a fairly unstressed 200HP engine and over the years Volvo ended up getting more and more horsepower out of it by adding bolt on superchargers, intercoolers etc eventually 265HP (Kad 300) out of the same old basic block. I think reasonable power gains are safe? Even the D6 is gradually becoming a more and more stressed member what are they up to now 350, look at the D4?