93 URS4 Cat removal? Check engine light?

[Algernon]

I'm pretty new to these cars so hope someone can give me some answers please.
I have the chance to fit cat replacement sections into my URS4.
I was told my car has had a "phase 1" something or other????? and should be running close to 300bhp. I'm not certain, it gets a move on when I floor it, shows/holds 1.6 on the digi boost gauge wot and I haven't taken a look at the ECU to confirm any chip or not..
My question is: If I replace my catted exhaust with these de-cat sections is it likely to throw an annoying light up on the dash, possibly restricting boost or revs? Any other running problems likely? Do you disconnect the lambda wiring from up top and store or keep them plugged in and coiled up?

Is it worth doing if my car is either standard or otherwise?

Thanks

[gedu]

Welcome to old cars

ECU wont know about missing catalysts. Keep that lambda plugged in and in exhaust, without lambda connected and IN exhaust ECU will throw a hissy fit and your MPG drops.

[AndyP]

Dash board boost reading on the UrS4 shows absolute pressure, i.e. boost + atmospheric pressure. As std it should read around 2.1bar and if it has a chip around 2.5bar. you probably have a boost leak, search on here for solutions.

[S2central.net]

Yeah - that 1.6bar on the UrS4 display is 0.6bar boost - sure sign of an air leak and/or dead N75. That or a faulty MAF or throttle pot.

100% agreed with above on keeping lambda probe plugged in - ECU will not be happy about that at all, but you can happily deCAT without worrying about anything.

[martinjs]

Where did you get the cat replacement pipes from?

[Algernon]

Jeez!! That means hopefully that when all is well it should pull even better! Blimey, I'd best get that fixed!!
It goes well enough already but does seem a little slower to rev and less instant than another S4 I've driven.
I've been reading on boost leak resolving but not certain I have the tech skills or equipment to carry them out but i'll try and see what I can do by elimination.

Martinjs it's a second hand system with home fabricated bolt in/out sections. I don't remember seeing any Lambda probe in it though.

Thanks all

[sal_s2]

I got some cat bypass pipes on my one if you want mart?