Firstly, clutch was slipping etc and a rattly noise appeared also - bearing in mind this was an 18 year old car I decided to get it checked out... but it got worse in the interim.
The oil pump failed and ruined my 1.8 4cly M42 engine... Rebuild was £1-£1.5k, another engine the same would be about £500 fitted...
I have since had a conversion done for £600 (very good price) to a 2.5 6 cyl litre M20 engine - including clutch, gearbox, exhaust etc...
Electronics issues - minor - electric mirrors not working when I bought it, brake pad sensor light always on.
The 1.8 16V chain-driven engine I had was very revvy but torque left a little to be desired.
The 2.5 12V belt-driven engine I have is still fairly revvy (esp running on the older 4.10 open diff) but much torquier...
Instant boost from 137bhp to 168bhp and 129 ft lbs torque to 166 ft lbs iirc.
Feels it too. Goes like stink now!
Handling is sublime. The steering is precise and well weighted, the M-Technik suspension is beautifully composed and the original 318is state it was in meant it had the disc brakes all round anyway, so it copes with the 2.5's power well (someone pulled out in front of me recently and I stopped in time, in the wet!)
Traction in rain is a bit messy sometimes, but respect the car's limits and it will respect you.
It's a RWD car which means I will need to learn it better to understand it and control it in case of mishaps - I will also be taking on track days to really get to know the car.
The engine conversion is a great move, even though fuel costs have increased this can be subdued by resisting the temptation to floor it, as it gives good highway miles (same as the 1.8 imho) and it's only stop start traffic and revving hard when tempted by the thrill of the engine that leads too bad MPG.
What can I say about the look of the car? It's faultless. My particular car has a Zender body kit on it which gives it a subtle upgrade to a meaner, lower look. It is not garish, just gorgeous.
Even in standard guise the car looks good, but I am very happy with my purchase because the kit sets it off beautifully. It's stunning.
I also bought it with leather sports Recaro seats as opposed to the cloth Recaros you get with the 318is, and this is one thing I am stupidly glad about - I knew I'd miss the leather from my Primera if I bought a 318is and this came along and sold itself to me.
The seats are comfy and although the leather is somewhat worn, they are still pretty neat looking.
The interior is brilliant in that it is driver-orientated. The heater and stereo control console is facing the driver, the steering wheel I have is the 325i Sport M-Tech 2 steering wheel - comfy in the hands, leather and a joy to behold. Roomy up front but not so much in the back behind my tall 6ft 2 frame, but it can accommodate enough for my needs!
The boot is spacious and came with (most of) the original toolkit, the jack etc and would easily fit a great sub and amp install if one were so inclined. I enjoy the space as three people can take a decent sized bag for a weekend away without too much effort, so may avoid such ICE installs.
I think that covers it.
I basically have a 325i Sport without some of the luxuries, so it is a lighter car, and it cost me a lot less than a proper 325 Sport would cost - and is cheaper to insure! I cannot complain. I wouldn't suggest you do the same unless you had no alternative - I couldn't find another GOOD 1.8 M42 engine in time and this was a last resort, backed by a great deal on the conversion - a price hard to find again, ever.
Note that the weight balance on the 1.8 is better than that of the 325 and it is a higher revving engine with a similar top speed... Each has its benefits, but the torquier 6cyl is said to be the choice of the lot... And the sound the 6cyl makes is incredible ;)