I have just done the bigger (330mm) brake conversion on my 2005 3.0i se,and have the carriers from the original calipers for sale now,if u want them. (one of the calipers was sticking,or u could have them too;but u can get good refurbed calipers from budweg/with a 2yr warranty far cheaper than bmw).
PM me if u want them,
and u can have the carriers from my 3.0 for £30 the pair plus postage(which will need to check/tho should be around £10 or less).
P.s,i will happily throw in the Calipers from my 05 3.0i as well,if u want them(f.o.c). 1 is in good working order/the other will just need refurbing/if u want them;just cover the extra postage and they are yours.
You will probably notice a good improvement from 2.2 to the 3.0(05),as i did with 05 to 330 calipers,etc. a decent bit of extra bite