SX4 ZxI Petrol - Advice needed on 20K Kms service

Hello everyone. My SX4 ZXI is now 18K kms old. I had got the last free service done at 10K kms. This one's going to be paid. I am going for a long 2000kms trip to Saurashtra next week so decided to get the car serviced. I need some advice on what should be done: 1) After 10K kms the air filters have not been cleaned, whereas the manual mentions it should be cleaned every 2000kms. Can I do this myself? Should I get the filters cleaned or changed in this service? How much would it cost? 2) Do I need to get wheel alignment and balancing done? The car has not had a single puncture till now (touchwood) and does not vibrate even at 140km/hr speeds, so is this required? What would be the charges? 3) I had got put synthetic oil (don't know which make, probably Mobil) at the 10k service. Does the oil require to be changed / topped up? 4) Anything else I need to get done at this point?

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