Just install a Magnaflow muffler in place of the resonator, and delete the two rear mufflers (just run straight pipe from the Magnaflow to the rear and use the exhaust tips of your choice). That's what I did. Sounds and runs great.

I paid my local muffler shop about $200 for the work, which took them just under two hours (not the cheapest shop around, but their work is good - I stay away from muffler chains). I bought the Magnaflow muffler off E-Bay for $80 and Hedman chrome exhaust tips w/resonators from Summit Racing.

xpipe... do it... sounda great.. runs great... cheap modz!

Be careful just blindly installing an x-pipe. I removed my center resonator and had a reputable local shop install a Magnaflow x-pipe with small Magnaflow resonators behind it to get a bit better flow. It was a disaster. I lost so much low end torque that I couldn't tow my empty trailer in 6th gear, let alone the loaded trailer like I could with the stock resonator.

Yanked it out, put straight pipes in and had the shop fab a basic crossover pipe between the straight pipes out of 2" pipe. What a difference! torque was great down low, pulled the trailer with ease, and a nice sound running just the stock rear mufflers.

Here's what I've discovered since then after chatting with a few folks who understand the American V8 hotrod market. The x-pipe is very sensitive to where it's placed in the exhaust stream. And it should be an equal distance from each exhaust manifold. On our X5's the distance is far from equal with the left side having to travel a lot further than the right, so the exhaust pulses going through the x can fight each other for space rather than "follow" each other through. A simple corssover (should be about 75% the size of the exhaust tubing) is much less sensitive to those distances.

I know others here have had luck with the Magnaflow x-pipe, but in my case I lost a good 50hp and a bunchy of torque. OK, it flowed really well at 5000 rpm and up, but that's not where any of us drive, we need the 2000-3000 torque on a daily basis and that's where my engine fell flat on it's face. And not being able to even maintain 65mph on flat highway in 6th gear with the empty 1100 lb trailer behind me was the killer since I can pull the loaded 4500 lb trailer on flats in 6th just fine.

I didn't go the magnaflow route, i had a great local shop fabricate one custom! I gained a bit of power for sure.. not sure how much or if it even makes too much a difference, but it sounds great and i havn't missed a step on.

Glad it worked out. I doubt you gained any power, however. These SUVs are so big and heavy that you'd need to gain some serious power to really feel it. All my exhaust change did was make it louder and more "aggressive" sounding. Still, I like my X5 better than the overpriced 2008 M3 I had.

Really? X5 better than 08 M3?? I love the 08 M3!!!

I'm sure you're right about the HP gains, but huge gains don't matter much to me. I do know that I like my car just a little more with the X-pipe, the aggressive tone feels good and real, it shows off the great motor.

I think where you went wrong is adding resonators in addition to installing an x pipe. Typically you're supposed to remove the resonators and install the x pipe in place of it. 2.25" is the diameter to go with. Also, there's no real need to have anything custom made unless its going to be cheaper than a mass produced unit. Custom piping is not going to increase anything or outperform one from magnaflow, for instance.

There's a lot of people that are making it sound a lot more difficult and complicated than it needs to be.

I went to the shop with full intent to have them install Magnaflow, they said, we usually fabricate our own to spec for the car. next thing I know they're fabricating this wild x-pipe, it came out very cool and yes, it cost me less than if i were to install a magnaflow. It fits perfectly, no overlapping seams and everything it flush and strait. magnaflow is a good "brand" and someone can have a proven design, but I'm happy with mine.. i should tell you that i went to a very well known and trusted shop with highly skilled craftsmen, not some corner meinekete, although, i'm sure if you went to mienekete with a magnaflow x-pipe, someone there could help you out.

I went with the x-pipe and the small Magnaflow resonators on the recommendation of a couple of folks here. My goal was a bit more power but still quiet. The resonators are much smaller than the big moster piece from factory so there's absolutely no reason the car should have lost power with supposedly less restriction. But rather than spend more bad money to try the x with out the resonators, which would have meant more custom pipe work, I just went to the h-pipe crossover. Tried and true technology and easier to fab up than another x-pipe. Perhaps the x by itself might have worked but I wasn't going to take the chance.

So would doing a resonator delete and an H-pipe achieve the same goals as an X?