FIVE WAYS TO MAKE IT BETTER

1 STAY RUST-FREE

With corrosion becoming an issue, it’s worth keeping a close eye on the bodywork, and dealing with any outbreaks as soon as they appear. Specialists also advise a regular check of the underside, looking for rust on the brake and fuel lines, the former being especially vulnerable – replacement is around £500. If they are a sound, then a liberal coating of protective wax or oil will keep them that way.

2 A PERFECT DRIVE

Taut handling is an M3 trademark so replace any sloppy suspension bushes. Budget around £250 to replace worn rear shock absorber top mounts, while front wishbones bushes come in at around £100 each. Original parts are best and done on a preventative basis, costs aren’t prohibitive and it’ll transform the way an M3 drives.

3 ENGINE MAINTENANCE

There’s always the potential for bottom end wear, so if an S50 engine has covered 100,000 miles then replacing the connecting rod bolts and main bearing shells is a wise precaution. Upgraded parts are available but OEM bits are perfectly good, and you should budget around £1000 at a specialist. The work can be done with the engine in situ, too.

4 KEEP IT COOL

A cooling system that’s deteriorated through age and mileage is risky for such a powerful motor, so an overhaul is worthwhile. The expansion tank can fracture, so a BMW replacement at £90 is a cheap fix and while the £370 cost of an OEM water pump is heftier, it’s a wise move in the longer term.

5 GO ORIGINAL

Modifications to the brakes and suspension were popular, but many prefer originality so you might consider a return to standard spec. Original BMW brakes all round are £880 for the parts, with springs and dampers coming in at £1500. Not cheap, but it will add desirability should you come to sell.