leaf spring? PCM/ECM?

Well i was just wondering i need new leaf springs from my 2001 cherokee and was looking around i found ones from quadratec, and also i found procomp 2.5 inch leaves on ebay. Im guessing this lifts 2.5 inches. i was wondering if anyone ran these and if i got them could i just get a spacer in front and have like a 2inch lift? I would just buy a 3 inch lift kit but im scared that ill need an SYE. But if anyone can give me input that would be great. Anyone on here have a 00-01 with a 3 or 3.5 inch kit without SYE?

Also how can you tell if you have a bad PCM/ECM?

thanks

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