thre is alot of stuff available for the SPI
FC makes a cam gear, UDPs, TB, Race headers, shorty headers and ORPs. once the FC tb is on your SPI pretty much any aftermarket intake will work.
i'm pretty sure all flex pipes work and i know all the exhausts do.
EFP(
http://www.escortfocus.com) has cams, springs, retainers, lifters, head packages and even a 50% reduction Race UDP and a Split-port controller.
the Clutchnet clutches i have are also available for the SPI's IB5 tranny.
a SPI with all the bolt ons, some valvetrain work and a cam with a 50shot would be a very solid performer.