With the exception of rather unusual airframe/equipment certification issues, there is little point in an N-reg unless you have an FAA PPL/IR at least.
I own an N-reg and have an FAA PPL/IR (soon hopefully a CPL/IR) as well as all the old UK stuff (and used to be on G-reg) so I know a bit about this.
Whether to buy or join a syndicate (post PPL) depends on one's budget and how well identified is the mission capability requirement.
If you learnt to fly to seriously go places (abroad etc) then getting a PPL & IR and purchasing a decent IFR tourer right away is a very good strategy. All the hours spent banging about in spamcans is wasted if your objective is beyond that. Currency on type is just about everything in this game and the sooner you start accumulating experience on what you really wanted the better.