I cannot comment on the year of 911 to get. Having said that the early ones such as the 99 are more attractively priced. Myself I prefer the coupe but each one to their own.
One thing to add when your tech does the PPI is to make sure that the engine is fully warmed up so an accurate code reading can be taken of cam deviation. A cool engine will likely give a different code reading for cam deviation which is not what you want.
Do your due diligence, try and get service records. Patience will be rewarded.