Your suspension wouldn't be locked out - that would be only if the arms were on such an angle that the ball joints physically couldn't move anymore...
You might find that the SPC arms just don't have that much adjustment. The upper control arm is where the adjustment comes from - pretty sure the SPC arms have a sliding ball joint like most, however the locking bolts are on the side of the ball joint rather than on the top. I'm assuming that your 2.5 degrees of adjustment is 2.5 total, so only 1.25 degrees in or out from any point.
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