Never know, it depends on the year E55. In the SL55's the first couple years were 72mm but toward the later years (before the new model), I believe 06+ maybe 07, the SL55 TB's were 80mm.
Only get it if it's the 80mm TB, otherwise I don't think it's worth the time to make it fit
Got this from the MBWorld site, from Vadim @ VRP
Early C32 TBs can be bored out from 74 mm to 76 mm. IMHO, on C32 that would probably be worth 5-10RWHP. Going with 80 mm TB will work and will add another 5-10RWHP.