I am considering using one for a DL55...... other than noise restrictions, do they make more power the same or decrease power?

In my set-ups I've found that I'm losing maybe 200 rpm to the canister over the straight through exhaust style mufflers, such as DL, MT, Brillelli.

If you use a quality canister like MTW or KS it will be about the same with the proper length. Tony and the like overseas are coming out with some but they are too short and not designed properly. I lost rpm with those ones.

I gained RPM with an Evolution 45cc MTW pipe. I got better transition and power after I cut the header shorter. Anything with a header will change the powerband. It now swings a Vess 22b to 6900 RPM

I lost the same with my Brillelli 366, DA header, and Ks1090 canister. I know if I tune them I could probably could get it so I'm not losing the 200 rpm, but by the time I got it in the plane I'm not going to take it all out to cut the header then reinstall it, maybe having to repeat that 3 or 4 times. I'm willing to lose 200 rpm and have it quite, both my Brillelli and MT have great throttle response and take the planes OOS vertically.

No canister for me then, noise isnt a restriction at my site

You might want to go to a tuned pipe then, you really have to tune them, but you can get huge power gains.

A rather mixed bag of results for me:
MTW75K resulted in 6900 with a XOAR 23A prop
KS1060 tuned pipe end result 6900 on a XOAR 23A
Chinese can designed for 60cc dropped my RPM down to 6200 Xoar 23A

I care not to use a pitts style anything!

i saw last weekend a yak with a DA 50cc with canistar...and wow, where the sweet noise of a gasser is?. I didnt like how it sounds with canister. Of course im a noob so maybe im wrong.:

If you are looking for a power increase then you want a tuned pipe. Properly setup you will gain 500+ rpms and spool up will be super quick. Should be able to turn a 23x8 Mejzlik around 7500rpm.

i would like to go that route but my plane only has a place for a canister, im sure installing a TP would require butchering my yak

MJ,try the canister from MVVS-Evolution,it is about the only canister that i know of that will increase your power and RPM's.keep your header short as possible.

Any of the canisters will increase power increase available torque - OR allow more rpm
the setup is what makes the difference
homemade canisters can and do increase torque and done properly will raise the max torque and the rpm at which that occurrs
some are intended for the "bolt in on and hope" guys
but-what works at one rpm may not work at another .
in a nutshell
to increase power -you must BURN more fuel- and a decent canister will allow really good exhaust flow without causing "out of sync" pulses back into the engine
which are best?
I like the old JMB- pretty tolerant of header length
not any real boost over open exhaust but a nice quiet tone
I don't like noisy engines
tuned cans ?
YOU have to set the right length for the rpm.
And that depends on the prop load

I'm from Belgium, a country that is absolutely hostile to aviation an other hard disciplines so model airplane pilots have a hard time to survive here, for all kinds of reasons. Let's say we are tolerated for the time being. Pitts style mufflers are absolutely not alowed over here , so when we order a modell, a canister tunnel must be provided which is in many cases a problem because many manufacturs don't take account of that.
A canister complicates the engine plant considerately, as I said you need space to put it and it must be properly mounted or you have
nothing but trouble with it even when you don't care about rpm loss. I have had some trouble with failing headers as long as I use them and they are quite costly. If you don't need them and you are already deaf or you don't care becoming it, don't use them I would say.