Need Help On Some Modifications. Review on Bullet Electra

I have a Royal Enfield Electra 4S 2010 model . Its Just an awesome bike . Really a head turner in city . Besides some minor glitches during early period of ownership , everything is great . The handling is better than any other two wheeler . Average is also good with 33-35km in city and 42-45km on the highways(without Pillion) . What I really dont like is the size of the rear tyre . Its just too thin for a bike of this size . But I also understand that it is necessary for the mileage . Also there is some small misalignments of mudguards but that will do . Feels so safe on the highways . 90-100 kmph on highway can be held continuously but I ride around 75-80 kmph just to feel the thump of the beast which I feel is a little less. The odo reading is 13000 km which I know is alittle less for I bike this old . The pick Up is good within the city as well as the highways . Brakes are descent but I do feel the absence of a front disk . The rear brake is also good and the first brake shoe change took place at around 10, 000 km.The bike starts in max 2 kicks even after 2 weeks. The clutch cable is a little on the harder side though.

There is some diminishing of pick up with the pillion and the mileage also decreases by 1-2 km , but what can you expect from a 185 kg machine. The usual speed breakers and potholes dont have any effect on the riding . Front shocks are great but there is a usual problem of oil leak which I have heard from many bulleteers but  have encountered none. Rear shocks also work well. Seats are comfortable , even more than that of the Saddle seats of Cl350 . Paint quality is excellent and the shine of the bike is still like new , of course with some maintenance .

I want to know something from you guys . Does changing the 'stock air filter' with some better one increases the 'pick up' and 'mileage' and if yes , where can i get it from in delhi and which model of filter . One more thing is that if i change the company fitted silencer to the short bottle silencer of the older standard 350 model will there be any effect on the engine or the performance(mileage and pick up) . I just want to increase the thump of my machine.

Everything is just unbeatable about this bike . Must have one of these once in your life . Thanks and looking for a speedy response .