dragaholic

ok today I went 15.1 @ 88 mph. 92 si eg with 205/50 zr15s dunlop sp 9000 street tires. 2.2 60ft. spear,tools etc removed. Do you guys think I can see an improvement with the rear seats removed?
I can also get my hands on some toyo ra1s but I'm wondering if I would see ne improvement since they are 205/55/14s.
just a note I use to run 15.1s @90 mph with the same type of tire(2.4 60ft) almost completely worn. Is it because they were worn thats why I was trapping higher mph?
Timing is set at 16 degrees, would bumping it up to 18 improve my et.

Any suggestions? Thanks