I went Whipple over KB because of price and I like the looks of teh Whipples better. Now that KB's no longer have that breadbox look I may have gone with the KB Mamouth Kit. Both are great blower.
The SRA is mild build for dratrack duty. It has all solid bushings and a Detroit/Eaton Tru Track diff , and 10-way adjustable shocks...so it is not as smooth as IRS but still feels good on the street IMO. Plus I like the idea of 5,500 RMP launches with out fear of breaking a halfshaft. Link to the rear build Soild Axle Build for '03 Cobra Coupe - SVTOA Nashville Forums
The IRS brace is a good Idea I had a brace on both of my IRS's...better safe than sorry. Unless you want to upgrade injectors, fuel system and other stuff I'd stick with the port and the spray.