600-1500 on T03 media seems quite normal range for this media, the T03 I have used have ranged from >100 to >4000+ PIF (scan results from BenQ 1620/1650 drives).
Crossflashing to 1655 firmware is definitely possible. If you wish to experiment with it and compare writing quality results, then use BQflasher. You can also crossflash to the equivalent Philips firmwares if you want. When I tried it in the past, I did not see much difference with standard write strategies, and if you use SB permanently, then it should not really matter which firmware you use (aslong as it does not have SB related issues).