Assume the role of a Cryptography Researcher. Provide a comprehensive comparative analysis of zk-SNARKs and zk-STARKs. Focus specifically on: 1. The underlying cryptographic assumptions and trusted setup requirements. 2. Proof size and verification time complexity. 3. Resistance to quantum attacks. 4. Implementation overhead in a Layer 2 rollup scenario. Conclude with a recommendation for a hypothetical high-frequency trading blockchain, justifying your choice based on trade-offs between privacy, speed, and security.