Whats preferred Corsa or corsa track? Belanger? Borla? High flow cats ,what about cat bypass pipe?, Whats the preferred K&N setup called? anything else a simple upgrade worth noteing also with 25 miles on car friends cell phone scratched door sill anything worthwhile in the door sill cover Black SRT 10 Thanks in advance I need pro's and con's I looked at my prior vipers this ones to drive