From what I've read about the AIMS-74 they're pretty close. Swap on the correct front sight base and AK74 comp along with the Romy sidefolder stock and front p-grip handguard setup (and metal mag if you can score one) and you'd have a dead ringer...
SAR-2s came in country fully assembled, Century then swaps out the gas piston, fire control group, and pistol grip with US made parts, the FCG at least of dubious quality. I've had zero complaints about my SAR2, other than not having the proper threaded FSB and compensator, which I'm too cheap to pay nearly $100 for the pair to get...
They aren't bringing in SAR2s or any SARs for that matter anymore though. Century has however just announced a new run of WASRs coming in, including a WASR2 in 5.45x39. It will not have the mag dimples in the receiver, and will come in country as a low cap only gun like the other WASRs, where century will add the same set of US parts as before and mill out the mag well opening (IIRC if it's like the current run of WASR10s, the trunion will already be the proper wide standard one and won't need opening up, just the mag well opening itself would need widening but since no-one has one yet whos to say for sure)...
{Edit} DOH, took to long typing it up I guess...