Ill find more pics but you get the idea. I have long tube headers on the truck now and with the 2.7L im in the low 15's with the 30" tires.

This is the solution for your exhaust you will get the rumble and the power.

I made this exhaust about 5 years ago. I think in total i used 1 90 deg and 2 45 deg bends for the front Y pipe. The rest of the exhaust was one 28" resonator and i think it was 2 90deg and 1 45 deg for the over axle.

Well....I got a couple of quotes from the muffler shop.  They can do a cat-back with 2 1/4 pipe, dynomax super turbo muffler, 2 1/4 tailpipe and 3 inch stainless tip for $200.  Or, they can start at the end of the Y-pipe with the 2 1/4 pipe, replace the stock final catalytic converter with a new universal free flow model, then continue with the rest of the goodies from above for $350.  He didn't really think the second option would produce a lot of gains, other than what I would get from a new catalytic converter versus my 10 year old one that's on there now.  What do you think?  If I go with a larger y-pipe, it'll probably drone, right?  Not to mention, it would probably cost a lot for that y-pipe to be made.  My converter is ancient, so I'm thinking about the $350 second option.

is there a part number for the newer Y-pipe?

or is there a place I can get it cheaper than from the dealer?

I have a 2.5 V6, is the newer Y-pipe going to be a straight fit ?

Yes, Bosal makes a y-pipe for the Grand Vitara.  Part #783-247.  Walker also makes one.  Part #52384.  Both can be found for between $90 and $150.  Death to rip-off dealerships!!

It's funny....I checked an online Suzuki parts site that I always buy genuine parts from, and all model years of the Grand Vitara have the same manifold and y-pipe listed.  However, the center pipe with catalytic converter, muffler and tailpipe have different part numbers for 99-01 versus 02-05.  Makes me draw the conclusion that the extra 10hp for model years 2002-2005 comes from just the center pipe, final cat, muffler and tailpipe. 

It's funny....I checked an online Suzuki parts site that I always buy genuine parts from, and all model years of the Grand Vitara have the same manifold and y-pipe listed.  However, the center pipe with catalytic converter, muffler and tailpipe have different part numbers for 99-01 versus 02-05.  Makes me draw the conclusion that the extra 10hp for model years 2002-2005 comes from just the center pipe, final cat, muffler and tailpipe. 

How are you able to rule out changes to the engine?

Well.....changes to the engine can't be ruled out completely, I guess.  I had heard that they tweaked the exhaust for the extra power.  While there are certainly no major changes to the engine from 99-05 (virtually all parts that relate to core function and power are the same), there are different ECM units, and they may have played with the computer to tweak things a little bit.

It doesn't tie in with your dates, but the EPC shows a different set of camshafts for MY 94-95.

Camshaft is listed as same part for 99-05, so there's no difference there.

That probably means the new camshafts are interchangeable with the old; i.e. they don't carry the old parts as replacements.  That doesn't rule out that the timings were improved.

e.g 99-03 Camshaft RH 12710-85FA2 and 12720-85FA2

      04-05 Camshaft RH 12710-85FA3 and 12720-85FA3

The Bosal and Walker pipes are stockers and look to be just as restrictive.
Some questions, how much for a repo of that y-pipe and long tube headers? where from? And dual exhaust, what is done with the o2 sensors.
Btw, just changed the gasket between the y-pipe and converter. As much as I am a Zook fan, have 2, why build such a great little engine and stifle it with that exhaust system?
 And Happy New Year

The designer probably optimised his design for good torque at low rpm (which is what you need for off-road). 

Fitting a larger bore system will add power at high rpm but will reduce scavenging (the action which helps to empty the cylinders of burnt gases) at low rpm, and will therefore tend to reduce torque.

Life is full of compromises.

Happy New Year!