As I've stated previously, the track pack are terrible, terrible shocks. I've dynoed them and they are laughable. I don't know who signed off on them...... We've pulled many of them off cars. The problems with the rest of the Bilsteins are well-known. The base shocks are very soft and have very little control. The sport pack shocks lock down the valving to keep the tiny shafts from moving so they are very harsh and have the oh-so-enjoyable Snap over-steer that I am sure many here have enjoyed spinning across an autox course or track. The track-pack is the cream of the crop(sarcasm) because the springs are too soft, but they are adjustable from harsh to harsher on on the knob. lose-lose :P It is easy to thrown rocks, but I am glad that Lotus cut costs here because it is easily fixed.
With the Penskes, even the NAs, we use the full-size body, Piston, and large shaft so there is alot of fluid displacement with minute shaft movements. Fluid movement = control capability. Although we are using the larger body and shaft, they are lighter because they are aluminum bodies and pistons.
A couple of different ways to go. The NAs with 350/500 are a great all-around offering. Much more controlled than the bilsteins and though firmer, are less harsh on the road and responsive for the track. Drop the spring rate to our "cruiser pack" and it is more comfortable than base bils.
Some folks like the Single or Double Adjustable, but put the 350/500 from the NAs on there. Plenty of adjustment in the valving for it. This gives a plusher ride on the street and dial up to even racier on the track.
Mattjk, you could try the base shocks, however, they are borderline too soft on the elise, I don't know where you would end up with the heavier car. That money could be put towards the Penskes. Obviously, we're biased, but I started this because I am a Lotus enthusiast and I wanted to fix the issues for my own cars.