Yes Alot Haris 
Bro problem is 2.75 tyre is looking a bit thinner & ruining looks of bike as well
you are right 2.75 is not troubling at rear its working good
Gul no problem of bumps with rear tyre its working good
front tyre was alot bumpy and it was 6PR tyre @ front that was a new thing
as exactly same service tyre is installed in deluxe but it has 4 Ply Rating
Even in pridor manual its also stated front tyre 2.75 4PR
But My Pridor has 2.75 6PR tyre at front
and i think that is why it was giving lot of bumps even on straight road at higher speed
Yes mostly company fitted tyres work very good no need to change
them or increase their size. But Its about enthusiasm
and My Pridor stock front tyre was not working good for my bike
thats why replaced with same tyre size 2.75 but more better tyre
I personally prefer changing tyre with same size tyre
but i am little compel to get litter wider tyre for Pridor
Will change tyre size minimum after 1000km
Some time ago i had seen a tyre Ghauri 3.00 18
which was feeling pretty light weight also
I don't think it gonna put pressure on engine
inshAllah would replace & check if there is decrease in fuel average or in pick
The Concept Of AHl Engineers Is Quite Awkward To UnderStand
All Over The World In Motorcycles You See Front Tyre Is Slimmer Than Rear Tyre
But Its Opposite In Pridor Front Tyre Is Fatter Than Rear Tyre
That Is Big Reason I Want To Increase Width Of Rear For Better Grip, Balance + Looks