I suggest for rims get the stock rims. they look best on this swift. however if you want to go for after market rims then try lenso. they have a nice look as well. apart from that in tyres first you should select a brand. turanza comes in DLX which is a better tyre however people prefer Yoko db's that come in DX because i guess they are much softer. I still prefer turanza...better build for pakistani roads. best way is to get an online tyre size checked and keep the allowed limit well under 3-5%
However im attaching a link here for your convenience. Keep the stock rim size of 15....will last you long as suspension won't give problems..
Tire size calculator
the stock size is 185/65 R15
Hope it helps
For navigation, in my opinion the best way is to get a tablet (if you have one then don't get another) running Android OS and then get Sygic maps installed on them. Sygic maps has FULL Pakistan's map and will work flawleslly. They are updated well on time too.
On the other hand the navigation being offered by Suzuki is crap. The sound quality is pathetic as compared to Aftermarket headunits and the mapping system is based on Sygic's own software but not the updated and innovative. However if you still want a DVD unit, get a branded one like Kenwood and Pioneer and use a tablet along with them. or even stick to the stock unit that came and get a tablet and connect it with aux wire to the head unit. will work as DVD as well as Nav unit.
Hope it helps