Straight Pipe vs Topgear Sport

Hello all I'm a new forum member and this is my first post. I'm based in South Australia and I've had my 996 for a little under a year. I have graded from a 2.5 Boxster, that my mother now drives. My 996 is an early one, built in October 1997. One of the factory options that my car has is M150, no cats. The previous owner performed the Fister mod, and, whilst it sounds good, I wouldn't mind if it was a bit louder. I recently had some straight pipes fabricated, however the noise was egregious. I've been able to take a few bit of weight out of the front of the car but taking weight out of the back is proving more expensive. My main goal with the straight pipes was to get weight down, and I dropped about 20kg. I know that I'm not going to be able to drop that sort of weight whilst maintaining a less obtrusive sound, but I'm trying to get the best balance of weight loss/legality. Without the cats on the car, it's louder than a standard 996, but I'm wondering if anyone has any experience comparing the Topgear sports exhaust versus straight pipes? I've seen the fantastic video on YouTube byThe Throttle Cable where he compares the weight of the Topgear mild vs OEM mufflers. I see that this will drop around 7kg. I'm wondering if the sports mufflers would be lighter than the mild mufflers? I appreciate any advice/experience.

straight pipes will be louder but also less metal and thus less weight muffer sizes, smaller = lighter

I've directly replaced the Top Gear 'loud' silencers to Top Gear 'mild' and whilst I didn't weigh them, I cannot remember noticing any difference in feel lifting one off and putting the other back on. The difference in sound was significant though. The loud ones are very loud, the mild ones are lovely and mellow by comparison, but still have a nice bark when loaded.

Did you, perchance, give the car a bit of a noise test when you had the mufflers off, to compare?

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Feeling lucky? Loud. View attachment Clip TG Loud.mov Mild. View attachment Clip TG Mild.mov The microphone does a good job of equalising the volume and doesn't really showcase the difference in overall loudness, however the tone difference is accurate, in that it with the mild silencers, in music terms it sounds like the treble has been dialled back a bit and the sub-woofer disconnected, but still with 'normal' bass levels. Hope that helps.

Very helpful, thank you. Here is mine with straight pipes..

Here's a clip of the outside rear with the loud silencers. It did sound amazing, but way too loud and obnoxious with deafening, almost painful interior drone and resonance. View attachment TG Loud Rear.mp4

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I paused the video after 12 seconds because I couldn’t handle that sound. You’re made of stern stuff.

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What manifold and cats are you running?

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In those clips, TG headers and TG 200 cell sports cats. I've since removed the sports cats and replaced the originals, as I was still getting some drone. Now with the standard cats on, it's much better and sounds just right to these old ears.

My previous 996 had the Topgear sport mufflers and standard cats when I first bought it. It sounded great below 3k, but very loud & awful drone above that. So much so I could only drive on the motorway if I wore some ear protection. I eventually swapped them for some switchable boxes which were much better. The switchable ones had a similar quality of sound in sport mode, but without the drone & less noise, then I foolishly added Topgear headers & 200cell cats, which made sport mode virtually unusable. It's subjective, but I think for most people the sensible compromise would be stock cats & a switchable system OR mild boxes with 200cell cats.

I've got the TG Switchable on my turbo with sports cats. It's a straight through 3" pipe with the valve open. I think the turbo does a pretty good job at muffling too. If it's an NA car i wouldn't even consider running a straight pipe without a cat.

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Yep, mine came with the headers, 200 cel cats and loud silencers and it was utterly ridiculous. I couldn't drive it with the windows closed as the interior drone was painfully loud. Even driving obout on very gentle throttle and low revs, everyone would turn and look and I became 'that' guy. On the basis I know what I think when I see 'that guy' with the loud exhaust, they had to go. Headers and milds is just right for me now, but I'm getting old and I'm not down with the kidz.

I've got some TG headers and 200 cell cats to go on mine when it goes back on the road imminently, I went down this route for rustproof longevity and I'm a bit worried it's going to have a negative impact on the loudness as that wasn't really the objective and as Interference Fit says, I don't want to be 'that' guy. They'll be paiired with the existing Design Tek back boxes which were a little on the boomy side already, I guess I'll just have to see how it is when it's all fitted...

It seems as if fitting the 200 cell CATs with the more open back boxes = excessive noise/drone. Contrary to Sp1ke I have standard headers & CATs with the TG Sports boxes and it’s fine for me. Not loud at low RPM and great when pressing on, neighbours haven’t said anything and I’ve had many compliments (although Dad says he knows when I’m visiting if he’s outside!). On long journeys with the missus I notice that it’s not a quiet car (also CAI mod/HHZ removed) although she has never said anything. The only drone is on the motorway at 3000 rpm in 6th gear (= 70mph) so I just use 5th gear until above if sitting at that speed for a while. The cabin rattles annoying me more!