i have a 2000 bonneville ssei with the L67 and was wandering wat mods i should do first i was think of an intense fwi and an overdrive pulley for the sc how small can i go without any internal engine mods

Before mods happen, you need to make sure your engine is as tuned as it can possibly be.

This means new filters (fuel and air, if they haven't been done in a while), new plugs and wires, O2 sensors, maybe a top-end engine cleaner.

You will also need a scanner, preferably one that shows realtime data, and shows things like KR (this goes back to that other question you asked). If you get KR, you need to find the root of the problem BEFORE modding...otherwise you will make it worse afterwards.

A cold-air intake would be the first thing on the list....it usually is.

I would defenetly go with soem type of cold air intake, like a FWI, or some type of cold box. Then change your thermostate. After that you can think about pulleys. Gettign a new tuned PCM woudl be a good idea after your base mods are done.

thanks but does any1 no how much boost my car makes stock bc i dont wanna od the pulley 2 much and have 2 pull timing

No boost gauge?

Stock you're probably around 6.5psi I believe.

Start with a 3.5" SC pulley and go from there. Sandrock is right, tune up first or ASAP.

yes i have a boost gauge but it isnt working properly at the time so if u could tell me that would b great

Try following the vacuum lines going the MAP sensor(*). It'* fairly common for one to pop off at one end.

8 PSI is the usual peak boost, but before you do any mods, you MUST fix whatever problem your boost gauge is having. It may be affecting the boost reading going to your PCM as well, which could easily result in a MAJOR problem.
Like everyone else said, make sure your engine is in top shape before adding stress by doing mods.

thanks the line had poped off now it works perfect
thanks again