Originally Posted by coswurv

They are alot sronger and reliable, the standard bolts are fine when new for the engine power etc there designed for but at this age you cant guarantee how many times they have been undone and done up, over tightened etc, for the sake of £50 its money well spent as a broken big end bolt will ruin your entire engine.

Originally Posted by RSandy

modified engines tend to be driven harder and revved higher, and its high revs that would cause you to throw a big end bolt.

these are just more up to the task of the higher powered n higher revving engine