My advice is to find an alignment shop that has experience with sports cars or even racing cars. Perhaps it's worth the drive to take it to Roger Krause Racing in Castro Valley. As Comp 2 mentioned, the OEM specs are mostly meaningless unless you're running OEM tire sizes.
Just for fun, here are the alignment specs for a Ferrari F40; which has similar suspension, weight distribution and 245/335 section width tires.
Front: Camber: -1°10" to -1°30"
Toe-in: 1.5mm to 2.5mm
Caster: 5°10" to 5°20"
Rear: Camber: -1°0" to -1°20"
Toe-in 2.5mm to 3.5mm
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