Engine Tuning, if I was starting now, I'd go for the Forge Intercooler, Milltek Downpipe and a Remap from Mr. Knox. You could go for the Alta intake or just put in an ITG replacement filter. For that you're probably looking at around £1200 plus fitting? Not sure of the up to date prices, but it would be cheaper and more effective power-wise than the JCW Tuning Kit. You get an upgraded inlet manifold and cat-back exhaust with the JCW kit though...
The JCW Suspension Package is pretty good, and is certainly an improvement over the standard setup. It still prefers smoother roads and can be a bit jiggly over some of our crappier roads, but I'm happy with mine and have had some fantastic drives with it. You might want to look at some good quality lowered springs and a set of really good tyres (like my Michelins) before you start chucking large sums of money at suspension kits though. I've found that tyres are a major factor in being able to enjoy your MINI, so don't fit fancy suspension and rubbish tyres! You'll probably get decent results on standard suspension and the best rubber.