Some members have reported slipping clutches with only the EZ, some with the EZ and 275 injectors, guess it really depends on how you drive and what you pull. My OEM clutch never slipped with the EZ, but I wasn't towing, just drag racing in my own way. IMHO, you will probably be okay with just the EZ box, unless you are pulling real heavy loads. I changed to the McLeod when I upgraded injectors, because I knew from others experiences that the stock ETH clutch wouldn't hold up to the BOMBing path I was following. The EZ alone is a great power upgrade for the ETH, actually lowers the egt's while giving you a real kick in the pants. I'd try that alone first and add larger injectors only when your wallet will allow for a new clutch. Be sure to install the boost elbow when you put in the EZ box.
Scott W.