Challenges in terms of overlaying of /libs/cq/personalization/components/target/engine_cq.jsp

As we know that

Final (granite:FinalArea) - Defines a node as final. Nodes classified as final cannot be overlaid or inherited. Final nodes can be used directly via sling:resourceType. Subnodes under final node are considered internal by default like the below one - 

But now I need to add some custom logic in following file /libs/cq/personalization/components/target/engine_cq.jsp as per my project requirement.

To overcome this challenge one idea has come to mind and I would like to share it here so that all of you could review and share your thoughts :

Here is my approach - 

I need to manipulate  List<Teaser> teaserList in engine_cq.jsp.

Already I have decompiled the OOTB[TargetedContentManager] service and bundle associated with engine_cq.jsp and identify the method exactly where I need to add my custom logic so that it will work for my project and won't make any impact with remaining AEM sites.

Problem with the above approach is if we do upgrade then we will be losing our changes[custom logic].

@arunpatidar  @Jörg_Hoh @kautuk_sahni @lukasz-m @anish-sinha and others please suggest alternate approach also.