Not sure what you mean with the first part of this post.
As far as high lift or fast reving engines(fast ramp rate lobes) causing coil bind or broken springs. A properly installed set of springs will far out last the biggest and baddest springs that are just thrown in.Provided you match the right springs to the right lobes. I really cant image Pac1518s with stock hardware being an issue with the ms3.

 

As cheap as Retainers and Locks are..I cant see geting new ones..They rarely is a problem with them new or used but..it cant hurt..thats what I was geting at..I agree as far as installing the springs correctly but they can wear out..and if someone drives the hell out of their car..its a good idea to go just a hair bigger and go with good stuff.

Example.. MS4 .649 Lift on the intake side...650 lift sprigsn..thats cuting it damn close..I went with .660s..last a bit longer..I think..but Im not an engine expert at all just what I think that makes since