i really liked my HTRz3's but yeah i had 275's
and they were not 500
the finger gap is an irrelevant measurement...its middle of fender above the center of teh hub from the ground. thats the best way to measure your actually height. finger gap depends on offset/camber/tires ETC ETC.
i'm sure you've seen my car. i was not slammed but was pretty low and that was mainly achieved because the tires eliminated a lot of the gap.
for the time being yes go lower, but the rear will end up cambering in more and over all it will just hurt the car unless you get roll center kit and rear camber adjustable arms to dial in your camber. also if you go lower i hope you're getting and alignment because while camber is livable with TOE is what actually kills you tire wear.
: if you ant 275's dumb your car now and let the toe shred your 245 tires while it handles like ****