N54 JB4 Map 2 - Do I need exhaust system or just downpipes? (135i)

[romnation]

So I'll be getting my 135i here in a few days and have already been looking into modding. If I'm intending to run map 2, what modifications do I need to do?

I've been following this guide and it doesn't seem too costly yet, but it doesn't account for a new exhaust system. Just catless DP. With the 135i, would I benefit with a new exhaust system? Especially If I am doing all these other mods? Anything else to know that the guide might not cover?
Here is the guide I am looking at:

http://www.armmotorsports.com/Articles.asp?ID=255

[ShocknAwe]

higher flowing DP are all that is recommended. Unless you're putting a huge turbo on the car there really isn't any need for anything else other than tweaking sound.

[xQx]

The stock exhaust from the bottom of the downpipes flows very well. The only reason to replace it to get the look of quad outlets or better sound.

100% of the (exhaust) performance gains are made by replacing your downpipes.

For map 2 you need a new chargepipe and downpipes. You also want a better flowing intercooler, but will get away without it. ... Also, you'll get away without replacing your chargepipe for a while, but the stock ones have a tendency to break under pressure - leaving you stranded on the roadside.

[xQx]

edit: wrong thread

[Jeff@TopGearSolutions]

Originally Posted by romnation

So I'll be getting my 135i here in a few days and have already been looking into modding. If I'm intending to run map 2, what modifications do I need to do?

I've been following this guide and it doesn't seem too costly yet, but it doesn't account for a new exhaust system. Just catless DP. With the 135i, would I benefit with a new exhaust system? Especially If I am doing all these other mods? Anything else to know that the guide might not cover?

That guide is helpful to someone looking to modify but it really doesn't explain the weak points of the vehicle, often overlooked (except the charge pipe).

If you're on a budget, I understand but there are better tunes, intakes, downpipes and intercoolers in the market today compared to what that guide may be offering.

Anyway, make sure you replace your spark plugs before tuning. Also depending mileage here a few things to look out for, old coil packs, old injectors, leaky valve cover, weak high pressure / low pressure fuel pumps, leaking oil filter housing gasket, water pump.

Water pumps tend to go around the 70K mark.

Injectors should be the last Index -12 revision (located on the injector)

Coil packs would be hard to tell but if they are original you should replace all 6, they are cheap enough nowadays.

Leaky valve cover will show signs of oil around the engine and or in the spark plugs.

The fuel pumps really won't show until you get deeper into tuning and usually codes will appear.

All those listed are the most popular weak areas of the car and often not maintained. As you push the car from stock and or just with mileage those aspects will fail depending.

If you are just starting out with modding get a Tune and Charge Pipe. After that Intake and intercooler. I usually suggest downpipes last as the FMIC upgrade (from a quality brand) does a lot more then any downpipes could. The stock FMIC gets so heat soaked that it doesn't matter what downpipes you have, every pull with heat soak will be that much slower.

[nwscoobie]

this is the same question I had as well. I am going that same route.