I know what you mean. I did all the Aire Valley stations on a West Yorkshire Bash a couple of months ago, and I was going crazy because of the auto announcer. Mind you, it's not as bad as the 1 used on 185s. That thing never shuts up! Makes it nigh on impossible to get any sleep!!!!
Aren't 333s equipped with 3+2 seating? 332s having the more spacious 2+2? I wasn't particularily impressed by the 332s when I went on the HE, I prefer the 360s of HC myself... the 332s do look more impressive though (and go fast through the Broadway!).
AFAIK 333s were originally 3 carriages but are now 4, whereas 332s are a mixture of 4 & 5 carriages?
332,s and 333,s were both built by CAF in spain with electrical equipment (traction packs etc) by Siemens, the 332's being built as prototypes for the british market and were developed for HEx, hence the SFE(sexy front end!!)
They were originally built as 3 car units, as the Heathrow tunnel was still being commisioned, HEx started up as 'Fast Train' serving a small platform (hence the 3 cars) at the entrance to the tunnels with buses serving the terminal areas using the dedicated coach lane on the M4 spur road, as HEx was launched all 14 units were made up to 4 cars, then as business built up another 5 trailer cars were ordered and were fitted to units 005/006/007/008/009, in 2003
(A follow up order was placed for the services now operated by Arriva Northern for 16 3 car units, funding was later found for a batch of trailer cars to make 8 units up to 4cars.)
Siemens at the time didn't have a body shell available for the british market and didn't have the facilities at the time to develop one, hence CAF's involvement, they were designed as a foothold in the british market, which was about to embark on a huge modernisation programme and Siemens wanted 'a piece of the action!' which they certainly did with the later class 350/360/450/444 and 185 Desiro's.
The units are electronically limited to 100mph (160kmh) but on test in spain were rumoured to reach a speed well in excess of this (120-130mph), at one time HEx were considering raising the service speed to 110mph but the extra maintenance and small time gain deemed it not worthwhile.
The same body shells incidently can also be found in Northern ireland's C3K DMU's.
HEx also has 5 class 360/2 Desiro units 201-204 as 4 car units and 205 currently the only 5 car unit (and not used in service as it currently can't fit in the headshunt at CTA, although this is to be extended and the route commisioned to T5 to facilitate this around the new year)
These units operate the HEc (heathrow Connect) stopping service to Heathrow launched last year, during 2007 the remaining 4 car units will be sent back to Germany and reformed as 5 car units (one at a time).
Incidently the 5 360/3's started life as 450's painted white and with gangway connections, we err hmm did a good deal with Siemens and had them rebuilt with full width cabs and converted to 25kv AC overhead units.