I don't hear too much about crossfire anymore, but I`m sure improvements could be made to solve any of the issues that people had with them...the only issue I could see, would be parts availability.
If anybody has any specific questions, please let me know, but EFI swaps like this are as easy as changing your intake manifold, whether its TBI or TPi. There are also single plane intakes from Edelbrock, with injector bosses already machined in so you can use all of the GM electronics, and an LSx throttle body. I scored the manifold, harness and ECM for $300, fuel pump was $120 at the time, Camaro fuel filter was $9. Then there are various fittings, which depends on how you taylor your fuel system.
All the parts on hand, this swap took me a weekend. Keep in mind, My 86 drivers side exhaust manifold was already set up with an o2 sensor. I ran on the single cat exhaust for about 2 years, and had the dual cats installed. The best exhaust combo for me, is 2.25 from the manifolds, to a Magnaflow Y pipe(unless you like it quiet like I do, then use a 14" case Dual in/3" out muffler in place of Y), and a 3" In/Out muffler, which resides at about a 45* angle, pointed up over the axle. I have dual 2" tailpipes, just for the factory look of the original 86.
Most of the square bodies have a fuel return line from the factory, so that is one headache avoided.
Manbearpig,
Yup, That was me! Gave you the lower manifold for the early heads for shipping.