Unsure of the make of the brake levers, but they are way more comfortable than the originals being nicely rounded. Being lighter and carbon bling is a bonus.
The seatpost is a MAVERICK SPEEDBALL , and allows 3 inches of infinite height adjustment "on the fly". Doesn't add much weight but can save you time/brown shorts when you reach the steep stuff.
For those interested http://www.whytebikes.com/whyte/index.html
where the E5 XT is RRP Â£2800, works is Â£3175. Mine would RRP a tad closer to Â£3400, but due to contacts and a nice employer is costing me around 1/3 of that - double bonus!!!
My upgrades where simply the speedball post, Tune Kong rear hub, King headset, carbon levers, Sapim CX Ray bladed spokes, and a few cosmetics like bolts, custom anodised rear mech and tartan fur saddle.
As you said, a shame to get it muddy, but that's what it's for after all.