Any rattle/squeak/noise could be related to RSMs or (worst case scenario) trunk floor tearing. 1-2 shift bang could be from this too, or the guibo. But yes, these cars are a bit tough to shift smoothly between 1st and second.
Also check your lower shock bolts. That's an easy 10 second job, grab a ~19mm (?) wrench, snug down the bolt that attaches the shock to the rear wheel hub bits. No jack required, just lay on the ground.