If the Macs for the ST is the same as the results (generally) for the OS-46FX/SF they have similar performance compared to stock and you might pay $30 bucks for another ugly one or for a Macs, whereas the Jett-Stream is a huge performance booster (bolt-on power) as is the Ultrathrust-

"A lot of people throw the ugly ST mufflers away. You can probably buy an ugly muffler cheap if it wasn’t thrown away first."

That is FUNNY BillS!

My new (used) ST G-90 came with some sort of boat-anchor bookend 2 piece steel-belted heavy duty all purpose muffler and a Bisson strap-on muffler (which I will use-)

Dave- I got a Tower-75 on my Funtana-46, what pop you thinking for low and slow? 13x4W maybe? (Not speed I know, that is why I am confused- the 10x10 APC may not be the perfect match for that airplane-)

Cheers!