New 04 GS... are my plans solid?

[GroceryGetter]

Hi everyone,

I’m from up north (Canada). 38yrs old, sold my last “muscle” car when I got married 15 yrs ago (77 trans am, 400 w/428 heads, etc, etc). For the last 5 years, I’ve been dreaming of a Buick Regal GS. Great family car, and a real sleeper.

Made the dream a reality just yesterday, a minty 04 w/32k miles.

This is definitely a DD, the kid’s car seat will be a permanent feature in the rear, and the grocery cargo net will see use at least once a week.

What I’m looking for is a mild mod solution that would hopefully give me a significant bump in street performance, without affecting drivability.

I have been doing reading on this and other forums for some time. I can’t tell you how much I appreciate the knowledge and insight of people that have taken the time to figure all this out. Until then, I’d never heard of “KR”!

Anyway, all this research has led to some fundamental questions, and I’m hoping some of the knowledgeable around here can help me with. I think the mods I want to do are as follows – 180 stat, 104s, manifold back 2.5” high-flow exhaust, cai ,3.6 (and possibly 3.4 pulley)

1) Assuming I’m scanning this thing, what is acceptable KR? I know the goal is zero, but at what point is it dangerous to engine health? Could it have KR bone stock?

2) There’s a local guy here that is advertising a 2.5” manaflow (at least the cat and mufflers are) off his wrecked 99 GS. Will it fit my 04? I have read different things about the rear o2… he tells me it has the bungs.

3) Assuming I can get the exhaust, cai, plugs and stat, will the 3.6 make a “real” difference in the feel of the cars performance?

4) Assuming I have KR under control, would the 3.4 be possible? Would the difference over 3.6 be that noticeable? This same guy has a modular 3.6/3.4 that he’s also selling.

5) At any point, should I consider the zzp PCM? Would it only be of some benefit after a pulley change?

6) The 04 doesn’t have the performance shift button. I’ve heard some say that you can ground a plug in the PCM or something. I am unclear on what would be involved, and if it would be worth it? Are there instructions or a kit for this that anyone has ever seen?

Thanks all, looking forward to building this car and sharing it on the forum.

Cheers,

-Scott

[mcgrath]

In an ideal world we all would like 0 KR but I think anything less then 2KR is ok. The 3.6” pulley will make a difference and if you can run the 3.4” it will be an even larger difference; you’ll feel the biggest bump in thrust down low. IMO aftermarket PCMs aren’t much a performance upgrade they help make the most out of what you’ve already done to the car, they just tweak things like fan points, torque management, shift points.

Ed

[GroceryGetter]

Thank you! Perhaps the most pressing question for me then, is would that exhaust from a 99 GS with the o2 bungs fit right in on my 04?

Thanks again

[mcgrath]

I would think so but I'm not very versed in many of the little things like that with the W-bodies; We'll have to wait for someone more familiar with Regals to chime in. In any case any competent shop could add an O2 bung where ever you wanted for pretty cheap.

Ed