Islamic banking rates depends upon the KIBOR rates too and their rates vary every year along woth the KIBOR. There werent much of a difference between islamic + conventional when i leased my car apart from
You pay after you get the car unlike conventional where you start paying after booking
You do not pay WHTax bcz thw bank buys the car but you DO pay a feww for the duration of booking which usually came out to be close to what the WHTax used to be. With less booking times, this should be a favorable option now
You can cancel/pay off after 1st day/month of your policy while you have to wait 12 month in conventional (not 100% sure about this on conventional)
Furthermore, Banks usually take out the loans on a yearly basis and KIBOR/Your installment will change after every 12 months solely depending on KIBOR. My payments are gonna go up 3-4% with 13th installments so you should expect an increase with yours too