FWIW, I love how my exhaust sounds. It retains stock manifolds, downpipe, and mufflers. Yet its louder than stock and added power. I drive quite a bit and the exhaust is exactly how I want it to be, its not too quiet, yet not too loud, and has very little drone. And on top of that, I know you can do it for less than $150. (should be less than $100 actually)
My car just has 2.25" pipe put in place of the cat/u-bend/resonator. Now your car has no u-bend so you will just be getting rid of the cat and resonator, however the cat is an emissions device so you might not want to pull that out. That leaves you with just the resonator, which I'm not even 100% sure your car has, but if it does, just pulling that isn't going to make a huge difference.
My suggestion for you is to leave the exhaust stock. You will regret it after a long trip anyways, drone is not too pleasant.
1990 Maroon Grand Prix STE McLaren 3.1 Intercooled Turbo, 14.695 @ 94.49 on 12psi before cam/heads/etc.
1990 Bright Red Grand Prix McLaren 3.1 Intercooled Turbo, 14.819 @ 92.72, 189whp
1999 Grand Prix GT 9.75:1|K&N|160 tstat|No Ubend/Cat/Res|UD Pulleys|Ported M90/TB/Heads|XPZ|2.55"|Pacesetters|Stage 2 I/C. 12.442 @ 112.78
2000 Blue Bonneville SSEi Supercharged Gutted Airbox|K&N|3.4"|1.9'*|WP Pulley|Custom DHP|180*stat|41932'*|No Cat. 14.681 @ 94.80
2002 Dark Cherry Grand Prix GTP Supercharged & Intercooled
12.084 @ 114.38 w/1.743 60', 315.6whp, Fastest Stock Cam M90 GTP!
NOW XP CAMMED, 340.6whp with XP, stock heads, Gen 3 M90, 11.984 @ 115.84 w/1.750 60'!
Most HP Stock Heads Gen 3 M90 GTP!
2004 Red Monte SS Supercharged K&N|3.4 Pulley|1.9'*|180*stat|41919 plugs|3" dp|No cat/ubend|DHP|Shift Kit. 14.2 @ 98
GOT BOOST??? Friends dont let friends drive stock!