whats a good way to beef up me motor 2L 99 tracker i got a k/n filter adding plugs next week what next

There isn't much you can do w/the lil' 4 banger.  Maybe squeeze in a 2.5 or 2.7 Zuki V-6.

Or better yet...

I suggest something like this... 

http://www.rocky-road.com/vortec.html

exhaust work helps, particularly pulling a cat and throwing in a less restrictive muffler.

Differential swap..  IF your feeling a lack of omph from larger tires.
Put in your signature line what yah got, will be easier to figure what you'd like.
If you put in your location in your profile, it may help pointing out suppliers.
 

there we go. it wont let me put a pic ? my computer too slow. a cat. converter ya i have to do that i think its going on me, i think it was trying to be a skid plate,lol i was looking at the small ones. i think it was a flow master on, muffler ?? thinking maybe cherrie bomb i think thats what i called the small round one, if not ?? as long as it sits up there tight. id like headers but all the ones ive found they say cant be used in a air cared inviroment. changing the diff ?? to what. i would like some of those 5;13 gears you guys talk about. they go into the trani or trasfer case?

You can do little things, Port out your stock air box, with a dremel clean out all the radius and put in a KN filter,

The exhasut manifold can be ported out with a die grinder, the exhaust put a 2.25" cat and full exhaust on it with a flow master or magnaflow muffler,run synthetic and new iriduim plugs,

Next summer when i get my house i will be pushing hard on the headers for the 2.0. I will make a full long tube header and exhaust and dyno before and after.

good - you can test it on my bucket

K/N filter i got that, im running royal purple synthetic oil, the plugs got them just need the time to put them in, next oil change ill put them in. the muffler and cat. converter will be after the kit. 2.25 cat   the size of the pipe, or the name of the cat. converter ??

Pick up a Carsound cat round body. there pretty cheap under 100us for sure. do a 2.25 off the manifold to the cat, then 2.25 back to a muffler and tip. Will pick up some ponies. Example just doing a 3rd cat delete on a v6 gv netted me pulling 2 lenghts consitant on the exact same stock gv . we tested it then put the delete on and noticeable difference.

Does the 2.0 have a manifold pre cat?

on the whole gear thing what would be better the 513 gear or the camini rock crawler gears ?

on the whole gear thing what would be better the 513 gear or the camini rock crawler gears ?

Check out the "Shift-On-The-Fly Removal" article for info on How Too.
http://zukiworld.com/month_030104/feature_tsb_shiftontheflyremoval.htm

If you have a manual you should have 4.62 Ring & Pinion.  If you swapped in the 5.13 gears, you could go from a 27" to a 30" tire without much performace change.  This would benefit you in high and low, you would keep your highway driving performace and off road close to stock.
http://www.izook.com/gearcalc.htm

Do a search here for the swap.  Don't need another thread on the diff swap.

Does the 2.0 have a manifold pre cat?

Sure does.

You could delete the secondary cat and it will make more power. The primary o2 is ahead of the cat and the 2ndary is behind the primary cat, Every car i did and truck with a pre cat passed the emissions with fliying colors.

You could delete the secondary cat and it will make more power. The primary o2 is ahead of the cat and the 2ndary is behind the primary cat, Every car i did and truck with a pre cat passed the emissions with fliying colors.

Are you saying you passed emissions with just a precat? 

What does the precat do vs. a regular cat converter?
I'm into more power but also don't wanna stink up the air more than it already is...

aren't there laws about the cats??