For sure, please try a different needle.
I've heard good and bad reports about the JD jetting kit, my own personal opinion is you'd be better buying a selection of 2 or 3 Suzuki needles, think this would work out better value.
Try the NECH and NECW and NECJ.
No, your bike doesn't need to be run HOT. Just get it warmed up gently before you give it any hard acceleration or high RPM but once it's up to normal running temperature it will perform fine...as long as it's jetted nicely.
All the best, Dave.