Need to know a bit more about the tune.
but in general you will be ok with the current tune.
removing restrictions is OK. adding restrictions is a NO without a retune.
assuming the tune was done properly & you have a nice accurate MAF Curve, more air in = more fuel in. (bunch of variables in how the ECU calculates this) but one big one is MAF curve. even better is a hybrid MAF + density
but for this you would need the ZR1 Map sensor.. sorry getting side track here...
so why would you need a re-tune than?
key word "Spark Timing"
since your timing was done with restrictions i.e. CATs
removing restrictions means less chance of predetonation. thats good!
but it also means you are now leaving power on the table.
you can see why going the other way is a no go.
if you tuned timing without restrictions and you latter decide to add them.
the ECU will assume it can get away with it when in reality it cant.
with that said, knock retard will kick in and save your engine, but its not recommended to rely on the KR to adjust your timing like that.
Conclusion: you'll be ok...
but the urge of extra power will take you back to the dark side and re-tune lol
