As others have said this is not a difficult job , and well within the scope of a confident diy mechanic.
It does help to take lots of pictures as you go along, and it also helps if someone else can do this as your hands will be VERY mucky (see John07's remarks above)
The fitting instructions are pretty good from SSL with lots of pictures, so you won't go too far wrong if you follow these.
I prefer the studding method too , but if you have a good hydraulic jack this can make the job quite bit quicker.
Now there is one decision to make , are you going to fit the supplied "spacer" above or below (the instructions do cover this)? A 2004 +8 is likely to have been fitted with blue springs from new (to improve the ride according to MMC!) which tends to give a "high" ride height. If you are forever grounding the gearbox crossmember on road humps then I would opt for the "high setting" (sorry I can't remember if this was above or below for the spacer) If you do not have issues with ground clearance, then this is an opportunity to correct the gap between the tyre and the wing by lowering the ride setting. Your choice entirely. I fitted it on the low setting initially and the car grounded on the way into my garage when it didn't before , so I had to take it to pieces again and reset with the spacer in the alternative position.
Getting the adjustable ride height setting correct is something of a challenge, just try to get it approximate first time , and then fine tune thereafter. It seems to needs setting again after a few months once everything has settled.
