Update:The system is running very smoothly now. I am monitoring the payment performance, it is good:
Total Execution Time: 0.081070232 Seconds
Total Execution Time: 0.0232471943 Seconds
Total Execution Time: 0.0747380257 Seconds
Total Execution Time: 0.0708121777 Seconds
Total Execution Time: 0.037799358 Seconds
Total Execution Time: 0.0891220093 Seconds
Total Execution Time: 0.0454879761 Seconds
Now I am open for ideas, what else to change/update/improve/add to the web-site?
Don't be shy ^^