ive done the mod just recently, and it is reversible
just make sure you ask your man to return the original baffles to you
once youve drilled out the spot welds, reversing the job to pass the pits would only take 30 minutes
with regards to your traffic safety concerns...
i am using MCS race baffles which are 3mm perforations about 12mm apart ie: < 10% open surface area
i know a guy with an 05 who has a nice set of yoshi slip ons and the general consensus is my system is about 10dB louder ie: 10x
the end result is when i am in traffic i can see people in cars looking around trying to get away from me, there is no tailgating :thumbup
much more obnoxious = much safer