Whoever you get to do your pre-buy, make sure they give you a checklist of Van's Service Bulletins that have been done / not done; AD list on Engine, Prop, and radios done / not done; and a list of last inspections done / not done on engine, prop, mags. This info should be in the logs with dates / times that appliance was replaced / inspected. (Yes there are ADs against radios/transponders.)
Have seen prebuy done on an RV-6 that had gone over 1,000 hours without mag inspections and buyer was not aware and had an unexpected expense for mag work.
This can help you in budgeting expenses that you will incur after you own the airplane.