Stick to the regular mineral oil for now since your car is just getting it's 2nd service. It is better to let the engine run for about 15,000 KMs before you switch to fully synthetic engine oils.
This isn't strictly accurate. As discussed in the initial post here, there is no demonstrable reason to wait before switching to synthetic oil. In fact, the higher detergent content would likely prove particularly helpful during the initial breaking-in stage.
Increasingly, new vehicles are coming straight from the factory with synthetic oil (contingent on the economics, of course) and never run on mineral oil through their lifetime.
It's better to have a word with your SA on this and I don't think it should cause any trouble as long as you stick to the recommended grade of oil.
Will synthetic oils improve performance? Yes, they do make the engine much more smoother and you can feel the difference once you get driving. However, you cannot just expect such good performance from any 'Synthetic' oil as it depends on the oil grades and good ones are expensive.
Completely agreed with this.
Do I go for Shell or at Hyundai Service center to put their Synthetic Oil which they used.
If Shell, shall I go for Shell HELIX ULTRA AH 5W-30.
If I change the oil at Shell, will Hyundai Service center object this?
Will synthetic oil improve the performance?
Thanks
Shell oils are typically some of the best out there, but I'm not seeing the one you mentioned anywhere. Do you mean "AH-L"? If so, that's about as good as it gets, with its SN friction rating and high durability.
Oil changes are simple. As long as the oil and filter quality remains consistent between the workshops, there wouldn't be much of a difference in the result.
What do you mean by Hyundai "objecting" to your choice?
@Astralbliss addressed the performance question already.