coilovers vs. springs/shocks

are there any advantages to running coilovers as opposed to just springs and shocks other than adjustability? i've been looking into a set of h&r springs with bilstein shocks on ecs as well as the the bilstein pss coilover kit. there is only a $150 difference between the two kits but i don't know if i would ever adjust the coilovers once they were dialed in. would the tt sit nicely on 18s with just the spring/shock (it says about a 1.5 to 2 inch drop) combo or would i need the adjustablity of the coilovers for it to sit just right? pics would be great if anybody has either of these setups. thanks.

another thing, how hard is it to adjust the ride height once the coilovers are installed?