For 2k you could get it running nice and handling good.
Engine wise, if you want to keep the car, drop a 1.3 into it. It shouldn't cost anymore on insurance if you re-register it with the DVLA as a 1.3
Like Ollie said, the Janspeed exhaust is a good upgrade and the full system is well worth it along with a K&N panel filter and extra air feed. If you running a non nats engine then you could get away with the 1.6 throttle body, ECU and injectors, the bigger TB will allow more air into the engine and therefore more fuel.
Another idea, as said above is to put in a set of cams, Piper fast road cams would be best as the ECU doesn't need played with and should provide you with another 8BHP ontop of the roughly 20BHP the exhuast system will give you with a good air feed. If thats done to a 1.3, you should roughly see around 110BHP.
Another option if you have the time and ££ is to drop in a 1.6 engine from an Almera, needs new mounts etc made but is fast.
As for handling you have 2 routes. You could get coilovers and a panhard rod, this will make the car sit as low as you want, can go down about 110mm I think, but height is usually adjustable. They are pretty stiff so not much roll but you do feel every bump.
Other option is to get uprated shocks, KYB, Koni etc and some decent springs, Eibach for example and the whiteline kit: Strut brace, panhard rod, trailing arms, camber kit, castor kit etc.
If your wanting it to look good and have decent handling then go the coilover direction.
If your wanting it to sit around 30mm down but handle like its on rails then go for the whitline kit as it is all adjustable and you can get it to suit the way you want.
Have a look at
www.micrasport.com
they have alot of tuning/performance parts for the Micra
