Advice Needed for My Upgrade Path

Thinking about getting a FMF Powercore 4 Slip On exhaust but I did some research before pulling the trigger on here because I remember various things about EXUP, fuel programmers, AIS, airbox flapper etc. If I keep the stock header pipes and go with the FMF P4, what do I absolutely need to do/get and what steps are not so necessary?

The EXUP is part of the exhaust, not part of the header.
Most would say you will surely WANT a fuel programmer, but more than a few have run aftermarket pipes without one.
The AIS is really for the stock exhaust stuff (catalytic converter) so you could take that crap off, but I don't think you absolutely have to.
You don't have to do anything to airbox either, and I wouldn't if you don't add a fuel programmer.

Ultimately, in the long run, you're probably gonna want to do all the stuff on your list, but you don't HAVE to right away. Not just for adding slip-on exhaust.

A fuel programmer gives much better throttle response, and I know this because I rode my 2008 WR250R back-to-back both with and without the programmer hooked-up.
The stock throttle response made the bike feel like it was running out of gas by comparison, and it just didn't respond as strongly without it.

Basically, if a rider is replacing the stock parts looking for some kind of performance improvement, I couldn't see why that rider would want to skip the programmer by choice.

The Powercore 4 is the louder FMF muffler, by the way.

I would also gear the bike down with a larger rear sprocket as it performs much better.
The bike comes geared too tall intentionally.

Things I feel are not so necessary are rim tape, custom graphics, bar end mirrors, polished frame or swingarm, aftermarket taillights or headlights, etc.

Correct me if I am wrong, but the only reason to put on a new exhaust without the fuel, and Air mods is to get a different sound. In which case, why bother?

More Air, More Gas, More exhaust. Only works when all are upgraded. Correct?

Gath3r13 wrote:

Correct me if I am wrong, but the only reason to put on a new exhaust without the fuel, and Air mods is to get a different sound. In which case, why bother?

More Air, More Gas, More exhaust.  Only works when all are upgraded. Correct?

Basically yes. Unless one has dropped the bike on the stock exhaust and damaged it.

motokid wrote:

Gath3r13 wrote:

Correct me if I am wrong, but the only reason to put on a new exhaust without the fuel, and Air mods is to get a different sound. In which case, why bother?

More Air, More Gas, More exhaust.  Only works when all are upgraded. Correct?

Basically yes. Unless one has dropped the bike on the stock exhaust and damaged it.

Excellent point motokid.

YZEtc wrote:

A fuel programmer gives much better throttle response, and I know this because I rode my 2008 WR250R back-to-back both with and without the programmer hooked-up.
The stock throttle response made the bike feel like it was running out of gas by comparison, and it just didn't respond as strongly without it.

Basically, if a rider is replacing the stock parts looking for some kind of performance improvement, I couldn't see why that rider would want to skip the programmer by choice.

The Powercore 4 is the louder FMF muffler, by the way.

I would also gear the bike down with a larger rear sprocket as it performs much better.
The bike comes geared too tall intentionally.

Things I feel are not so necessary are rim tape, custom graphics, bar end mirrors, polished frame or swingarm, aftermarket taillights or headlights, etc.

Was hoping I could skip the programmer since its nearly the same price as the pipe. Also, if I replace the exhaust, can I just leave the EXUP system connected without throwing an engine light? I don't have any solder experience so does anyone here ship the resistor piece pre-assembled on the cheap?

Also how many teeth would be recommended for the rear?

Myself, I'd go with 13/49 sprockets as I used on my 2008 WR250X.
It performed very well.
Longer drive chain needed, of course.

You can leave the EXUP servo motor plugged into it's electrical connector, but just remove the cables that control the EXUP valve in the stock muffler.
That way, no check engine light.

The "Sticky's" in each forum are your friend when looking to mod your WRR. Check them out.. A lot of good info in there.

The "Sticky's" in each forum are your friend when looking to mod your WRR.  Check them out.. A lot of good info in there.

I got my programmer before anything else, and I think it was a good choice. I noticed a bigger difference putting the programmer on than the pipe. I would think that getting the fuel delivery dialed in correctly is more important than making noise, and as has been said, the pipe will only make the bike perform better if increased air flow and correct fuel delivery are there to work with it.