What is the most important part of pre sales technical write up that is being read by decision makers?

Executive section in the first of the writeup is the most important part for decison makers as it summerizes the solution

The compliances to standards asked to meet the Standardization, attracts most to key personnel of technical team (client end), as it helps them to strengthen their assumption of the integration, in line of other System being implemented in the Project other than your proposal.

Exctuive summary which provide the benefits of the solution with regard to the estimated cost

Executive summary that elabrotes Customer Business Challenges, Pain Areas and how the solution overcomes it. 

SWOT analysis

Executive summary  is the first session of the proposal that gives an overview of the proposed solution 

Its the adherence to project compliance/need which is the price concern for qualification of Bid, commercial part comes later, once the proposal qualifies technically as stated in the System Requirement.

The compliances to standards asked to meet the Standardization, attracts most to key personnel of technical team (client end), as it helps them to strengthen their assumption of the integration, in line of other System being implemented in the Project other than your proposal. 

Technical proposal and the product value

Technical write-up must contain, objective, solution design, complete BOQ of the equipment's are the part of solution, technical specifications of all the proposed equipment's, dimensioning capacity of the solution, future up-gradation and interoperability with existing equipment's  in network    

Listen customer requirement / expectation , do not mess up it with GAP analysis. Note down all customer requirements / expectations. Fair it with business terminologies once you have refined requirement document , compare with your proposed solution . write down Key note for what you can offer from your solution that was not asked by the customer , in other case note down best practices normally adopted by world class solutions. Meet again and discus what additional you are offering them. 

Executive Summary.

Most of the decision makers don't have time to read the whole proosal, therefore the best way to have an idea about the overall proposal is through the executive summary.

To judge customer's requirement and find out the best solution for that...