some general questions on the car i will buy

[Bean]

depends on your budget and use of the car really - if you plan to spend extended times near the rev limit then some updated rod bolts would be good advise... if you can do all the work involved yourself it's a cheap safety upgrade as ARP rodbolt can be had for ~50US$

if you're lucky you could achieve your goal with bolt-on's only personally I would spend some money on top for a standalone ECU and have it mapped to get the most out of your modifications and if you plan to go further in the future this is something less to worry about. For mapping there is a good place just across the boarder to the north (DP engineering if I remember right - Steve from FC-Tuning is holding mapping days every now and again and can tune just about everything).
so engine wise I'd say: cams, headgasket, revising the stock exhaust where it goes over the axle or replacing the whole thing and ECU should see you hit your goal. Obviously there are a lot of things you could do too but mostly only with diminishing returns or serious money involved.

But first and foremost and probably the most valuable advise I can give looking back at 10+ years of thinkering with cars is: drive drive drive, there's nothinig more anoying to have a car that's not running so my advise is to focus on seat time and suspension - this is by far the cheapest recipe for loads of fun! I spent dozens of laps around the Nurburgring with the only mods being spring/damper combo, some adjustable camber tops and proper tires - I miss this now more than ever being so far away from racetracks/europe.