I have a relatively stock (so far) '07 Exige S, and one of my other cars is a Boxster S with a combo GT3/PSS9 suspension and a 320 hp Carrera motor shoehorned into it. The Porsche's suspension and brakes have benefited from many years of track development (by me), while the Lotus is relatively new to me.
The Porsches are great daily driver sports cars (although mine is pretty stiff and rumbly for the street), while the Lotus is much smaller, much lighter, much lower, and harder to get in and out of gracefully. And unless you buy one in a bright color, I'm not so sure that tall trucks and SUVs can actually see you if you're near one of the corners of their vehicles. So it's not a great commuter/trip/daily driver car in my book.
I would say at lower speeds and tighter corners, the Lotus is quicker, even with the more pronounced body lean (track pack suspension, more front camber via aftermarket steering arms, sway bar and shocks set to full stiff). Compared to the Lotuses, the late model Porsches are geared pretty high. At Fontana Roval (Road couse/Oval) I was able to hang with a lot of Porsche track cars in the infield until about 1/3 of the way down the front straight (where HP-to-apparent frontal area matters more, usually above 80 MPH) and then anything with more than 250 HP would start to walk away. I would say the Boxsters and Caymans are between the Loti and 911s in terms of nimbleness (although their engines ARE NOT designed for sustained track abuse...)
So I'm the least comfortable in the Lotus on a crowded freeway, but in the hills on a curvy road, I've never driven anything else so immediate and so engaging...
