The only mods i have done so far are;
18" RS8 replica's (225-40-18) with TOYO performance tyres (£600) miles better ride and handling than the stock 15" rims.
Ripspeed DVD player, with 7" flip-out tft Screen, Got a reversing camera on my trailor thats hooked up to it
Also have Freeview module hooked up to it, for in car tv.
Remap from chip and Spin (£250)
Towbar

(£40 from Ebay with electrics, fitted myself)
Mintex performance brake Discs and pads all round. (£120)
Oh, i did put some LED's inside the handles and wired them up to the internal light. So, at night when i opened the car the doors handles lit up blue.
I thought it looked cool, but then one of the LEDs failed and i thought it looked naff with just 3, so disconnected em.
If i remember i'll reconnect and get a pic, so you can tell me if you think it looks naff.
And thats about it, lol
Nick