I assume you are talking about 'power effects' they are black with oval shaped tips...
This exhaust doesn't look good to me, but it is one of the best... It lets you go from a setting close to factory, all the way to a setting like straight pipe.... there should be no negatives to this system
One word of caution, I saw a 91 ZR-1 which had the same exhaust you are talking about down in Orlando (Roger's show) and his complaint was that the baffle and linkage rattles depending on the rpm(especially at idle).
Just be aware of this before you make the decision.
I wouldn't have a problem with it but at the same time don't let it be a big selling point or be talked into paying more for the car because of the exhaust. Gains from aftermarket cat-backs on the Lt1 cars are minimal at best. I saw nothing in the 1/4 mi. with the addition of my 3" B&B.
just my .02
I put the Power Effects on my car a couple of months ago. It probably varies by car/engine, but the resonance is very significant, especially in the normal driving range of RPM's.
Also, I had thought that with the butterfly closed (e.g. close to stock exhaust flow), it would be close to stock sounding. Nope.
It goes from pretty loud closed, to really loud when fully open. Unfortunately, not sure how you know if it is acceptable or not without doing it.
Now the good news. A real quality system. I really think I can tell the difference in the cars performance. I don't mind the loudness so much because I do not have to drive it daily or commute with it. Usually, I am just "cruisin", and kind of like the sound.
p.s. I kept the old exhaust just in case, and suggest you do the same. Maybe good to have if you ever sell the car.