You can use an E series without a hitch! I'm using the Pearl right Now but I plan on putting it on my upcoming E90 as well. I had it installed on my E50 and my co-worker just got it on his E62 and it works as well as a traditional BB device. I think the Pearl is quicker and easier when it comes to email but without it, it's nothing more than a glorified rzr. Web browsing is so painful it's non-existant (and that includes Opera mini which runs really really slow). The sure type and track wheel are perhaps the 2 best features i've had on a phone though. For work the Pearl has proven to be a top notch performer so running 2 phones isnt bad either. I'll run with an n95 and Pearl until the E90 comes out then the pearl goes in the "drawer".