I usually keep it around speed limit+5 unless I'm pretty sure no one's looking, then I may go a bit faster*. Of course, the 240 won't do the speed limit up some of the hills around here, so it's third gear and floored for those times. The 240 is pretty loud at anything over about 64, but it sounds good to me.

*300D tops out at 110, the 240 was down to 75 so I changed fuel filters and got it back up to 81. Tires were a little underinflated at the time, so I'll have to check again now that I've fixed that too.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.