The Series 1 Roadster (I assume 2005 is Series 1?) has a very devoted following , and in many ways is the pick of the range, so you have made a good choice.
The first upgrade I would plan would be the modified sump to give extra ground clearance , especially if you live in an area infested with speed bumps.
Yes Series 1, and yes that would be the first change, also thinking about brake reaction bars and remote greasers.
